Probably any of the public store fronts will allow it. We always look for other campers doing it first but always go inside and let management know we are parking over night...
We have parked over night at many places other than WALMART... BASS PRO SHOP sometimes has 20A Service hookups to use...
Sitting at RV Dealer lots works too...
Got run off from a Church parking lot one time haha... I even told them I was Baptist - Still got run off...
Have stayed in many hotels parking spaces and gone inside and got donuts and coffee the next morning at their good morning bar...
Best thing to do is just go inside and ask permission
Roy Ken