The south fork of the Shoshone River is pretty awesome. I finally hiked it fully this September, and was surprised at how beautiful it was. It's more of a canyon, and you hike sections of it on ledges above the river. I kind of felt like I was in a canyon in Utah somewhere. You can make a loop with it while still going over into the Thorofare.
Hiking up tIshawooa Creek is a long haul almost entirely thru woods. The backside of Ishawooa Pass is beautiful, along Pass Creek, like kmatjhwy said above. Great camping in the upper meadows, and very remote. The upper part of Thorofare Creek, and over into the North Fork of the Yellowstone is a beautiful stretch, especially in the fall. I would do that over going down Thorofare Creek to Hawks Rest, So many options as to where else to go. North Fork of the Buffalo is an awesome area, and they redid the trail in there since the fires. Marston Pass, Buffalo Plateau, the Cub Creek area is all good too. If you go into Yellowstone, any of the camps along the river and lakeshore are pretty unique and special. Just a long car shuttle if your not doing a loop, and starting on the Washakie side. And I have to admit, that all of my trips in there have all involved info from
@Kmatjhwy from several years back. She is your best resource on here, along with
@Absarokanaut, who has also given me a ton of info on both the Washakie and Teton Wildernesses.