RE: camping at walmart
The above reccomendations are true about not being a nusiance. Escapees RV Club has printed guidelines for being a guest at Wal-Mart stores.
The only time we make an exception is coming home after a long trip. The day's drive usually puts us into Huntsville Texas where our daughter lives outside of town with an impossible driveway for a motorhome. We may stay two days with the grandkids in which case we ask for permission inside (manager if possible) and talk to the security explaining the situation.
Pick up any surronding litter left by someone else, return shopping cart to store.
As far as parks are concerned dumping large volumns of sewer doesn't seem very considerate although sometimes the ever increasing fees seem to be high enough to cover. What they charge sometimes includes swimming, spa, laundry and other amentites we don't want or need.
Last year we found a very basic park in the Oklahoma panhandle, no attendent, just a note to please leave $10.00 or so at a store down the road a bit, just water and 30 amp. Great for a one night get some sleep and leave. What a deal.