Eyegor wrote:
While it is correct that there is very few hard and fast rules, there is in fact acceptable etiquette. Not every one who overnights at Wally adheres to them but they do exist. They are like the "unwritten rules" that govern many things in a polite society. If you do nothing else, please go in and introduce yourself to the manager on duty. ...
Many of these etiquette "rules" are very subjective. WalMart themselves probably don't want their managers tied up with chatting with every RVer that comes by. I've stayed at dozens of WMs across the country and have never spoken to a manager.
You do need to make sure that your chosen WM allows overnight parking; in addition to municipal ordinances there are shopping malls that prohibit them in their leases. Call ahead and just ask whoever answers the phone whether they permit overnight parking "for customers who have RVs." You don't need to talk to the manager. While you're at it you can ask if there's anything else you should know like a specific area of the parking lot you should use, or should avoid.