Last week, I flew my RV-7A into West Yellowstone and camped for 4 days. Initially, I was the only camper, but another group showed up the following day. Most anywhere within the pine trees makes for an acceptable campsite as there are none that are specifically designated. The amenities are few, but adequate, a vault toilet and pavilion. No showers, electricity or night time lights were available. The nearby water spigot was turned off for the season as morning temperature lows were in the mid-30s. The daily highs reached into the mid-70s. The camping area was a short and easy walk from the airplane parking.
A rental car was necessary to explore Yellowstone and Grand Teton National Parks. Having the car helped to more easily access the campsite area from the ramp entrance, about 600 to 700 yards away. But, vehicle access to the ramp was restricted to the FBO operating hours, 7am to 6pm.
Fortunately, the adjacent EMT helicopter operation didn't have any callouts during the nights I was there with all of the noise a nearby turbine helicopter generates. There was occasionally some very faint highway noise but, in general, was fairly quiet at night. The perimeter fencing of the entire airport helped to ease any concern about bear intrusions. Something that is not true within Yellowstone park itself.
All in all, the camping area provided adequate accommodations and proved to be a good base camp to explore the park. Mountain flying awareness is critical as well as good VFR conditions for safe operations. Now that I'm cleaned up and warmed up, I'd make the trip again. Those 35 degree F nights in the tent were a little chilly.