PROVIDENCE — A trash-strewn parking lot sandwiched between La Gigantes Meat Market and a pawn shop on Elmwood Avenue has been home for the last two months for Matthew Roberts, his girlfriend and dog. Roberts has paid at least $100 a week and done work for the market’s owner in exchange for parking his 1992 Ford Econoline RV on the dirt lot. He's been told, though, that at the end of the month it's time to move on. Once again, Roberts will be in search of a safe place to park. “I can’t find anywhere to go. Even friends and family don’t want us there,” said Roberts, 40.