Our first campground in the park was at Mammoth Springs. It was a dry camping site for only $10 a night. We were able to go to a ranger program about the wolves and see the elk that came down into the area. Mammoth Springs is beautiful. You have to walk the wooden board walk to see the results of the springs. There are 3 ways to begin the trail, my suggestion is to start in the middle; lot easier walking. Lots of stairs to climb also, but well worth the time.