If you stay in developed campgrounds in the parks, the outdoor life is pretty civilized. You'll have running water and, in most cases, flush toilets, plus there are opportunities to meet fellow campers.
Norris Campground (Yellowstone): Although it's away from the hotels and services, the Norris Campground has excellent sites with a little elbow room, as well as flush toilets and the Solfatara trail head. A small hillside amphitheater hosts campfire talks by rangers. The campground is across the street from the Norris Geyser Basin and within walking distance of the Museum of the National Park Ranger.
Slough Creek Campground (Yellowstone): Another favorite is out in the Lamar Valley. The campground is smaller, but it's away from the crowds (and other services) yet close to fishing and wolf viewing. Because of the wildlife-watching and fishing opportunities here, it fills quite early.