At the time, and even today, many RV'ers will overnight in parking lots if they're in transit. Walmart parking lots are somewhat famous for this activity, however we've always found that there are better options.
Casino camping is one such better option!
Most casinos have large parking areas, and they don't mind sharing some of that space with RV'ers who wish to stay overnight. Some even have full scale campgrounds actually on the casino property, and many are at a very reasonable price. For our needs though, we prefer free camping. We're totally self contained and self sufficient, so we don't see the need to pay for hookups. You just need to check with casino security and ask if there is a special place you should park and make sure that it's okay for you to stay overnight.
Also, when you're free parking in the casino parking lot instead of being cramped in at a campground, you can normally park far away from other vehicles so that you've got lots of space.
Our motorhome Sherman, parked up for free with lots of space.
Casino camping has become so popular, that there are now both hard copy and online resources for finding a suitable casino to park at. There's a very popular book available, and the most recent edition has only just come out...
And also, you can search online...
And of course the best part is being able to go inside for some inexpensive entertainment. Usually, you can sign up at the casino players club desk and get some free stuff. Sometimes, they even give you $5 or $10 to start you off with some free gambling or one of the other casino bonuses. So if you're careful, you could actually walk out of there ahead of the game. Free camping, and some cash to boot!
Casinos always have restaurants, and very often they will have buffet restaurant special deals. In the morning, you can check and see if there are any breakfast deals worth taking advantage of.
Casinos offer a great free secure place to overnight. They always have 24 hour security, and cameras. If that's the type of thing you like, casinos offer a decent parking lot camping experience and usually without nearly as many people as your friendly neighborhood Walmart.