Not true dry camping or boondocking but we have spent many nights in 24 hour Pemex stations after buying a tank of gas and tipping the attendants more than you would for just gas. Also we have parked overnight in Walmart and Soriana parking lots. If there is security, and there usually is, tip the security guy 50 pesos and he will watch out for you. Maybe make him a cup of coffee as well. As I said, we have done this dozens of times and have never been bothered.