What was stated above covers it very well.
From my experience, Passport America is a bust unless your camping mostly excludes weekends, major holidays and 'tourist areas' like near national parks and such similiar places as those areas often don't give a Passport America discount from June into September so you pay full price
I travel with my propane on to keep the frig cold & never had a problem.
Some states, like Montana, require slower vehicles or those towing a trailer travel in the outside lane of traffic unless passing another vehicle.
IF traveling with a firearm, each state has specific regulations you need to check/follow & KNOW for legality for handguns and/or long guns ... being concealed, carry, loaded/unloaded, etc. Ignorance of the law is no excuse.
It's handy to do an internet check of each states Department of Transportation listing/map of roads under construction to avoid delays and detours.