My list for best camping that varies depending on locale: National forrest land, state parks, various strange and sometimes wonderful private camp grounds that are not KOA, and national parks.
Small national parks can be good - like great basin etc.., but generally you'll be crammed with people who view nature as a large petting zoo - and have little regard for noise, food, and garbage regulations.
National forests can range from primitive camping (free, but bring a trowel and some toilet paper), to more refined camp grounds. You can find some beautiful places - and real quiet.
State parks vary with proximity to cities and time of year - but they can be great. And if you're lucky they'll have a shower - awaesome.
When I've run out of road, I've stayed at rv and private parks, and in some I've had great times drinking and talking with residents, and watching strange events unfold. It's a matter of recalibrating what you expect and letting it roll over you.
Locale matters - Idaho is essentially a large campground - pull off most any road and set up a tent next to a river - other states vary.
August will always be the worst - more specifically - after july 4th until september - packed with people and RVs all over the road (nothing will kill your soul faster). Hunting season can be tricky - and when you're in a camp ground with signs that say "Please don't shoot campers" you get an idea of who you're dealing with.
In general you have to deal with the fact that people are pigs - every site I go to requires some cleaning - I always leave it better than I find it.
