>>976524This post is like %5 true.
>>976459There are huge chunks of land managed by two departments, the National Forest Service and the Bureau of Land Management, where you can camp pretty much wherever you want for free for up to two weeks. This land is mostly undeveloped, hence why it's free.
National PARKS are more developed, they have things like developed campgrounds with showers or RV hook-ups, lodges, restaurants, etc and they require an entrance fee and site fees if you want to use the developed campsites. Most of the larger ones allow backcountry camping, however. You can carry a gun in National Parks as well as NFS and BLM land, but you can't just shoot whatever you want. There are some basic rules about where you can discharge a weapon to prevent harming others. Hunting is allowed on NFS and BLM land so long as you follow the applicable state laws. Most National Parks don't allow hunting, but there are I believe about 50-60 that do allow hunting.
Also keep in mind that some National Parks aren't wilderness areas, they are historical or national monuments that the Park Service maintains.