Been there done that last year in June. We actually found a spot in a campground in Yellowstone without reservations!!! We were on motorcycles and tent camping. We left out of Yellowstone at daylight with frost on the bikes. When we got to the top of Bear Tooth we were in the middle of a freaking ice storm!!!!!! I think there is still a permanent wrinkle in the seat of my motorcycle!!!! We could only go in first gear due to riding them like dirt bikes so we kind of held up traffic. I think I would not be comfortable taking our fifth wheel and truck over that one..