I've only been to the ones in New Mexico.
One thing you might not know about. If you are of age enough, that is a senior citizen or a disabled individual, some US Forest Sites can be free of charge or, you may only be required to pay one half of the fee/s regularly charged to non seniors.
When I visited the dwellings in New Mexico, my admission was free because I obtained a Golden Access Passport.
Read more...Golden Age Passports and Golden Age/Access Passports will continue to be honored for the lifetime of the pass holder.
USDA Forest Service - Recreation, Heritage and Wilderness