Not totally true... You're not allowed to live anywhere you please in a motorhome, but you can legally live in any state if you rent a slot at an RV park and every state and most towns have one. The guy should have spent his money on a flat nosed school bus that could pass as a BlueBird motorhome with a coat of paint. They can be had for under a grand in goor running order at school district auctions, then the other 9k would put in a toilet, air conditioner, fresh and wastewater storage. I know, I did it. I spent four years legally living in my converted bus while I rebuilt my credit scores and now it's parked behind my house (also quite legal if you put it behind a fence in many towns). I'm not allowed to 'live' in it while behind the house, but it makes a hell of workshop now.
When I wasn't in an RV park ($300/mo rent) I would swap parking space at constructions sites for 'night security'. They were happy to have me on site until the places were getting occupied, then I'd either find another site or rent a 'lot' at an RV park.
One last little fact not generally known, Walmart allows overnight RV parking at all their stores. It encourages their owners to come in and buy the things they need for their trips.