Mina, I’m not too sure that you can do a loop trip on the Thorofare trail. Maybe a sort of lollipop trip, where you hike south, do a loop, then return the way you came in. The hike is pretty cool, since you are often within sighting distance of Yellowstone Lake (elevation ~7700′). Keep in mind that the Thorofare is an isolated trail, and if someone breaks a leg or something, help is a LONG way away. If I were to do it again, I would want a satellite phone, as I’m not sure about any dependable cell phone service along the route. Also, you’ll want protection from grizzlies that might wander on the same trail. Everyone in the group needs to carry pepper spray, and know how to use it without spraying themselves (or others).
There are some other trips that are fun, but some require a car shuttle. One that I’ve enjoyed was to start at the upper end of the Pebble creek drainage (this starts with a 1000′ grunt to get over the ridge that is the southern border of the Pebble Creek valley). Then about 1/2 way down the valley there’s a spur trail that takes you west over a pass that drops you into the Sough Creek drainage. This could be a 4-night trip, or longer if people want to fish the famous Slough Creek for a day or two. Slough Creek campsites are a bit hard to get, and I found that early in the season it is easier to score campsites, like around the 4th of July.
Perhaps the finest car shuttle trip is the Bechler River trip (5-6 nights). Logistics are tough though. First you need to pre-position a vehicle at the ranger station at the southern end of your trip. This involves driving west from West Yellowstone, then passing south through Ashton, Idaho to finally get to the ranger station in the far SW corner of the Park. Everyone would stay at W. Yellowstone, then drive into the park to the trailhead near Old Faithful to begin the hike. 2 miles from the trailhead you pass by the popular but very cool Lone Star geyser. If you happen to time things right, you’ll get to witness not one, but two back-to-back eruptions. It’s worth an hour of your time to see that if the timing is good. Then start your Bechler trek in earnest.
If the Bechler logistics aren’t your cup of tea, another variation on the Lone Star theme is to reserve the single campsite on the shore of Shoshone Lake for 2 nights, and spend the middle day exploring the splendid Shoshone geyser basin nearby. There are a couple of ways to do this – you could blast right by the Lone Star (noting exactly when the last eruption occurred – it happens every 4 hours, like clockwork) and push the group to get to the Shoshone campsite the first night (that will be a pretty long day; you could make it easier by staying at a closer campsite, and go on to the Shoshone L. site the 2nd day). The middle day of your 2-night stay will be exploring the geyser basin. The 3rd day could be an easy one, where you stay at one of 3 campsites on the way back to Lone Star. I like OA1, which is the closest one to the geyser (it’s maybe a mile from the geyser, and you can hear it erupt on a quiet night). Having noted exactly when the geyser will go off, you can pick which eruption you want to watch the next day, then pack up and leisurely walk the mile to check it out. Then make your way back to the vehicle(s).
Yellowstone is a very special place, Mina. It’s hard to go wrong, whatever trip(s) you choose. Once you get 1-2 miles from the highway, you leave all of the YNP craziness behind and immerse into perhaps the finest, most unique eco-system in the lower 48.
