@John4and @Kb9nbd , Yellowstone, being a National Park and not a Natural Forest it will have a lot more amenities at the campground including showers and a store where you can buy food and other camping supplies.  While one never wants to forget something and have to pay the outrageous prices at the NP store, it's not as huge of an issue. There will also be bear boxes at each campsite unlike in some National Forests. 

Found Myself Outside