Most of the cracker barrels I've been to teh RV spots are like 40-50 feet (usually 40) My Class A is 38 and I tow a car so I can either "Stick out" or "Drop" the towed and take up two places
Same at far too many Truck/RV spots too (like the loves in Fair Play SC).
As others have said,, But expanded.. The Campground Owners Association lobbies for state, county and local laws and ordinances prohibiting overnight parking of RV's anywhere OTHER than a licensed campground.. They often use the story of the RVer who Dumped his black tanks in a Wal*mart parking lot as a "Scare" tatic.
NOTE that I said "Story" not "Stories".
I know of entire states who have .. bought the scare.