E. R., skip sykes, it's just ruined, particularly during summer months. If you have good range / time you can hit Redwood camp, which is usually fairly empty, that's above sykes, and is the last redwood canyon you'll be in from the coast, plus you get to see a bit of the high chaparral terrain, but not so much as to be sweltering for too long. If I were to meet up with people on a trip I'd do it at Redwood camp because everyone stops at Sykes, but Barlow is technically better because it's got more options. Redwood however is up fairly high, not at the main river, and it's not really a canyon, just a stream that runs downhill to the main river, so it doesn't feel the same as the river spots.
Barlow if you go up or down stream from where the trail hits it, is really at least 5x better than sykes in terms of most of the things that make a spot nice.
All of these are 10x better than staying at point reyes, which is nice easy walking but really is just a very developed location, where all the campgrounds are over impacted, have picnic tables, pit toilets, bad tasting running water, dirt roads the rangers use to access each official camp, almost nowhere you can try for unofficial camping due to extreme poison oak infestation off most of the trails, nice, but a place I'd only use to get in shape for a real trip at this point. Plus it costs $20 a night or so, and the camp sites fill up in summer, you have to book in advance.
If you are aware of poison oak it's not that big of an issue, and of course, we are all immune to it until we are not, I believe exposure is what triggers the reaction, I never got it until I did, then I got it really bad. Some people need only one exposure, some need many, over years, some apparently never hit the limit at all and are spared.
If you want to maximize your chance of getting poison oak, I suggest walking through it all day to sykes, taking care to brush against the stuff that grows on the sides of the trail, get it on your shoes and pants too, make sure then to wipe your hands on your face too, then going to the hot springs there, where all the oil from all the people who have been in them for the last days is waiting to test your resistance as your pores open wide, that should do it, it did for me one year, which was the last year that I had resistance to poison oak, by strange coincidence. If you don't want to get it, then do the opposite of what I note here.
There are, as noted, ticks, and those ticks do carry lyme disease, permethrine is a wise thing to use on your clothing, and very careful nightly tick checks. A friend of mine from Alaska says he'd rather deal with Grizzlies than ticks, and I think I agree with him now.
Nobody mentioned biting deer flies, those are fun too, but they only hang out in the hotter areas, not in the redwood canyons, except for Redwood camp, because it's surrounded by the hot ecosystem. I've pitched a tent inner to have lunch there to avoid them in the past, they are pretty annoying, but are only around a certain time of year, the hottest.