We sometimes even pull into a hotel back parking lot and sleep the night. Always go let the hotel we are back there. Have never been turned down or bothered.
Of course the WALMARTs, Bass Pro Shops, Dennys, Truck stops, Bob Evans, Cracker barrels, etc are all open game... Even some RV Campgrounds have places in a large open parking lot to use overnite at no cost.
Some areas have ordinances against folks sleeping in their RVs overnite - Did get told that at a WALMART one time even tho we had checked in with management and had their blessings...
Never have much luck at the highway Rest Stops anymore. Usually got run off after a couple of hours. In the old days this was always to place to sleep-over until daylight - not anymore it seems...
One BASS PRO SHOP in central ALA was nicer than some campground we have gone to haha... They had the parking areas sectioned off with bushes and even had 120VAC receptacle you could plug into. They want you to eat breakfast with them the next morning and spend some money in the store I guess... We had some business close by and asked if they minded if we could back the next night haha they said sure....
Just read here about the casinos - have done that as well with no issues... Even a Church parking lot one time... I guess the only time those have cars in them is Wednesdays and Sundays... Actually we got invited one time as we had stopped to check out a church adjoining cemetery for family names. The minister drove up and was talking to us and told us we could spend the night in their parking lot if we liked.
Roy Ken