Not Ohio, but I did sleep on my car on the West Coast on and off for about a year and only got into trouble once. And I didn’t even get a citation, just an oral warning that this wasn’t permitted in that particular town despite there being no signs anywhere (it was written in the city code).

I will say, for all the shit that private property owners get on this site, Walmart is actually one of the places where this is the easiest and least problematic to do. I always tried to avoid private property in favor of more inconspicuous places but I frequently saw quite a few motorhomes parked on their lots after dark and they were still there in the morning, and I’ve heard from others that they’ll generally let you be unless you are causing some sort of ruckus there. Same goes for just sleeping in the car.

In general, if you’re not making a nuisance of yourself or parking right in front of a sign that prohibits overnight parking, you’ll most likely be okay.