[travelin texans]

RV Parky, Good Sams, RV park reviews are a few free good resource apps for rv parks.
As for staying in business parking lots, have NEVER done it, NEVER will do it & if I can't afford a spot in a rv park I'll stop rving.
I understand those parked in those lots normally go inside & shop or eat which should be mandatory, but the folks that own/operate rv parks are also in business to make money & probably could use the business far more than Wal-Mart.
My wife's brother in law has buckets of money, could afford to stay at any rv park, they travel from east Texas to Cheyenne Wyoming every year to the rodeo & "camp" at Walmarts all the way to & from every year. Not because they travel late & leave early, but because he's too damn cheap to pay for a site.
Not trying to offend anyone, just my opinion on the subject & I'm sure there's nothing I could say to prevent anyone from camping in parking lots, especially the cheap brother in law.