Never used a tarp. Deciding to use it for a long distance hike…

Insects like to have some shelter, too.

Don't worry about the spiders too much. It is the venomous snakes that will get you.

I worried about those things until I had spent about my first five nights out.

–B.G.–

I've been using a tarp since 2006 as my only shelter. I used one on the PCT in 2009 and the AT in 2012. I am planning on using one on the CDT in 2015. I love it, but it matches my camping style. I hate camp chores like setting up tents, so I don't do it unless the weather is bad. So I mainly cowboy camp (ie. sleep out side without a shelter). I use a bivy sack and stuff my sleeping bag and pad into it and throw it on the ground. Camp is setup in no time. Also packs up fast. Tarp only comes out when rain threatens. So a tarp/bivy combo works for my personal style. Other people feel the need for walls around them and they could never do that. Know yourself. If you aren't sure you are right for Tarping, buy a cheap one and try it out a few times and see if you are comfortable with it before spending the money on a better and lighter system. As to your specific questions:

INSECTS:
I always look for holes or signs of burrowing (something lives there and is best avoided) and crawling insects (mainly ants) before I setup camp. I've only had 1 night where crawling insects was an issue because I broke that rule. In 2009 on the PCT in Oregon, I was in the middle of a lava fiend with no flat area to camp except on the trail. I couldn't see what was crawling around under the lava rock next to the trail. So I got annoyed a few times by ants during the night. I have a few times that spiders came out after dark and were crawling around where I was cowboy camping, but they never bothered me during the night.

WILDLIFE ENCOUNTERS (when tarping or cowboy camping):
I've never had issues with snakes or scorpians, even when camping real desert. Never had a bear encounter, but I don't camp in popular campsites in bear country and I stop early to cook dinner before reaching my campsite. I did have a buck deer come through in the middle of the night that freaked me out because all I knew was it was big and thought it might be a bear. I think we scared each other about the same amount. I had a frog crawl under my quilt edge during a thunderstorm because I was camped between it and the creek. Once I knew what it was and moved out it its way, it continued hopping along to the creek. I did have a few mice encounters in some popular camping spots. One time if was so annoying, I ended up rolling up my bivysack with my gear and walking a short distance away to get away from the persistant rodent (it chewed into a tarptent through the netting during the night of a friend who refused to move). Never camp in a meadow unless you like field mice. Overall, I've only had those encounters on a handful of nights despite tarp or cowboy camping several hundred nights. It just isn't a real issue.

RAIN:
I use a solo size tarp with a lightweight bivy sack. You do need to consider your campsite selection more with a tarp. The lack of a bathtube floor means that if water pools where you are camping, you'll get wet. Avoid heavily used camp spots as the ground is compressed into a small bowl where the tents usually set up. I prefer ground with a slight slope to it. In heavy winds, set the tarp up low to the ground and try to find a spot behind boulders or in trees. I've always stayed dry. I also found that I have less condensation issues then my tarptent using friends, even in Washington in September. I don't have the issue of packing up a tent wet and having to dry the inside out the next night since my ground cloth is seperated and I can fold that up so the dry upside stays dry.

WEIGHT:
Some tarps and bug protection can weight more then some tarptents, but it doesn't have to be. However, my 2008 MLD Grace Solo Tarp in Cuben Fiber + a 2009 MLD Superbivy weighs under 15oz which includes titanium stakes + guyline. That said, cuben fiber is expensive.

ALTERNATIVE:
That said, if you want an alternative to a tarp, check out Zpacks Hexamid. You can have as much or as little features (such as bug netting, built in bathtube floor) as you want. For me, I would just buy their tarp (with no netting or floor) and use a bivy sack with it, but thats just me. MLD also has some interesting shaped tarp shelters.

A big enough tarp to handle bad weather is not much lighter than some of the enclosed shelters out there, imo it's more about the versatility than weight. When it's raining and not windy I like being able to set it up as a high canopy with lots of room.

To echo the sentiments of Bob, Sean and Justin, tarps do have a few distinct advantages. I personally have liked the bivy/tarp method, but I have been pretty much using a bug bivy and the tarp combo. A lot of nights I never even break out the tarp, just setup a bug bivy for cowboy camping. It is sublime. Certainly a more traditional bivy would serve the same purpose. But when you want a shelter (which is nice where there is rain or considerable moisture), a tarp can be setup to provide a pretty nice livable space. I have used an MLD Cuben Duo for a number of years, and find the extra space to be pretty sublime for a small weight penalty. Plenty of ventilation, room to spread out gear.

The downside of tarps compared to tents to me isn't so much bugs/animals but setting up in high winds. It can be tricky to do so at times – at least I have more a problem doing this than setting up a tent in similar circumstances. It requires practice setting it up for a variety of situations. I like line locs for that reason – easier to make some quick adjustments. I think it's also useful to learn to setup your tarp in a couple of configurations – maybe one with a higher "roof-line" which allow you to easily sit up and move around and another "storm" setup where everything is battened down for higher winds and possibility of sideways rain.

With the advances in some of the hybrid tents (such as the aforementioned Hexamid), maybe tarps have lost some of their appeal. I guess it depends on your style. I am pretty flexible and like tents and tarps. About the only thing I have had issues with is silnylon because of the sag factor seems to be a lot of hassle in wetter climates. Silnylon is incredibly tough and a great material, especially in dryer climes. The PCT is one-such example – it's incredibly dry generally through most of California and Oregon. I think the most rain I started to see was around Mt. Jefferson in Oregon and then Washington was snowy/rainy. But that had as much to do with hiking into October as anything.

Good luck! Go light!

Dirk

16.1 ounces total with stakes and a 3oz carbon ruta locura pole:

I tried a sul bivy but this net tent is just an ouce or two heavier and I can change clothes, read, etc. away from bugs.

edit: net tent is 7.9oz with stuff sack

Well, using a tarp is somewhat of a personal choice. There isn't a lot of difference between a tent and a tarp. Basicaly, they both provide a roof over your head in bad weather.

Besides the roof, and staying dry (which means good ground selection as others have said) there is the floor and body. Dropping these two means a lot less weight, but it also means good ground selection skills, and, knowing how to deal with bugs, and critters.

Ground selection is a bit of a chore. Sometimes you don't have a lot of choices. For example, I drive up to the ADK's ready for a two week outing. But it takes about 5 hours. My wife comes with me. So0, I am often stuck with a site that I don't really consider good. The wife doesn't care to sleep under a tarp (though, I don't understand why, there really isn't any difference between sleeping under a tarp and in a lean-to.) So we have two shelters. One is the tent for car camping and one is the tarp I will take on the trip. No choice with site selection means IFF it rains I need a good floor to stay dry. Out hiking, I can select a water resistant site, not one with pools or heavily saturated ground, but one with a small mound to sleep on. I use my pad as a ground sheet, even if the ground is wet, I stay fairly dry. I have managed with a down bag and down jacket, through several days of rain. It works, OK.

Bugs and critters can be a real problem. Near Little Falls, NY, there are quite a few Timber Rattlers…near Lake George, some of the southern tier, too. They have never come under my tarp. I don't think they really care about water, they care more about temperature. Tarps really are not that warm compared with a closed in tent. So, they are not atracted to the tarp. Bears are not really a problem. A tarp is just large enough, and smelly enough, they do not usually bother with it. But, it is safer than sleeping in a tent if a bear DOES visit… 'Coons can be a real pest. Bold and always into your stuff. Mosquitoes are perhaps the bigest downside to tarps. If temps are much above 60F at night, you need to use some sort of netting. DEET only slows them down, it does NOT prevent them from biting. Nor does permethrin, often they bite first and die later. Pesty basserds… Spiders, centipeds, and other bugs can also be out there to bite if you lay near them or their lairs. Avoid sand fleas/bed bugs near water sources. I got some in my bag that prompted me to spray it when I got back. An insect pad or two can be carried to eliminate them, if you stumble across them.

Anyway, this is part of tarp camping. Only in summer does the night time temps stay high enough to make netting required. I prefer the tapered A frame or diamond as a shelter against rain/wind. In nice weather, you can set up as a lean-to, sleeping towards the back. Check the sky first, of course. My total weight, including stakes, guy-lines is about 14oz. A 5'x4' piece of netting adds another 2-3oz, if needed. Again, ground selection is a critical skill to master. A mound, a slope, and under a tree (using it as a set up point) is my first choice. Second is a more open campsite with good drainage away from where I want to sleep. I would rather have a few roots under me than sleep in a dip. IFF I have to, I will pile about 6" of forest duff under me (not exactly LNT) to sleep above the local water level. You really only need about 20"x72" to sleep in. Sometimes between some bushes, works OK, and makes good tie-offs when I'm canoe camping.

Where and when is your long distance hike?

I tend towards an enclosed tent most of the time to keep out flying bugs, but do go with some sort of tarp when conditions make that seem the better choice, to include swapping along the way via mail on a long distance trip.

I would do tarp/bivy but even more likely, mid/bivy for the western trails. I would potentially switch out the bivy for a bug inner starting at TM on the PCT through OR and switch back to bivy in WA if it was late season. For the AT I would not take a tarp and would definitely take the mid with the bug inner instead. Why? More nights of rain, more nights of bugs and the worst of all heat, rain and bugs combined. This is where a tarp/bivy has its biggest weakness. Starting at Springer in the spring, I may carry the bivy rather than the bug inner until bug season along with the mid.

Now the important part, why. My biggest shelter criteria is flexibility to only setup those parts that are needed on a given night. On the pct I only used my tarp three times and cowboy camped the rest with a bivy. That worked great but using just a bug inner would have been better because ants were a nuisance a couple nights and mosquitoes only a couple. I have a net hood on the bivy but this requires being fully zipped into a sweat box. I would have used the bug inner because that can be setup in about a minute in a tiny footprint thus meeting all my requirements for speed of setup and tear down. One final thought. I believe a bivy alone is the best possible shelter in SoCal with the winds. You have a low profile and little if any flapping and super simple setup in the wind.

If you own a Contrail, why not! It is a compromise teeter totter of security/weather protection/weight and as you have surmised, there aren't any huge differences between a tarp and accessories and a tarp tent. I would rather sleep in the Contrail and I think is easier to pitch too.

I just sold my Trailstar and have a Little Star on the way (so the concept is the same). Can use this as just a tarp, albeit with lots of coverage, when the bug situation permits. I also have a Yama bug shelter 1.25 with a custom zipper in the ridgeline. This allows me to pitch as a standalone bug tent when the weather permits, a traditional bug bivy (drapes over the body with elevated head net) under the Trailstar, and with a little bit of creative cording a more traditional inner.

My wife isn't too keen on sleeping without an inner regardless of the situation, so I'll be picking up a Bearpawwd pentanet to house us both.

So the whole thing is very modular and able to suit my particular trip needs. Not much lighter than like a TarpTent Rainbow, but tons more space and i only take what I need. The Trailstar definitely has a big footprint, but that should be fixed with the smaller version coming in the mail.

One of the reasons why the Tarptent Notch has been popular is because you can use it as a tarp only giving you very good wind and rain protection 360 degrees, but you can also use it as a double wall tent with the option of attaching or detaching the inner whilst the fly is in place.
For hot clear nights with bugs around the inner only can come handy although I like just to leave the 4 door panels open so that if the weather does change I can be in locked down mode in less than a minute.
Not bad for 26 oz
franco@tarptent

A pure flat tarp sounds appealing – in theory.

But several posts here show that a single wall tent (with an optional floored netting) may be better.

As a confirmed tenter and "rehabilitated" tarper I recommend Michael L.'s setup with a Cuben fiber tent and floored bug net. In a storm you will be sheltered much better and as the rain or wet snow beats down on your tent you'll feel very cozy.

P.S.
If Cuben fiber is beyond your budget then Franco's suggestion for the Tarptent Notch is ideal. That tent is a design of near perfection – but then I'm a nortorious Tarptent fanboy.

Before I hiked the PCT I did the math on all the various permutations with the gear I had available, trying to see what combination of tarp and rain gear weighed the least (rain gear because some shelters can serve as rain wear.) I think the poncho tarp + bivy sack was the lightest option, the medium option was my 8×10 equinox tarp + umbrella (no bivy sack) and the heaviest was my Gossamer Gear One + umbrella.

In the end, I chose the tent + umbrella because of bugs. I simply cannot sleep with mosquitoes buzzing around my head. I'm glad I made the choice because it was simpler to deal with and the plague of mosquitoes I dealt with in Oregon was really bad.

I did use the poncho for a little while in the desert. That was fine, however it turned out that I could not actually wear the poncho since I'm too short. So I ended up having to carry an umbrella anyway, which didn't save any weight at all.