I don't know. That is a totally different situation. Me, myself and I wouldn't even recommend that sort of situation for a yorkie. They need room to run. A yorkie in that situation wouldn't have room enough to run inside the motor home and it wouldn't even have a yard. Do you see what I'm saying? I'm not trying to be mean, just realistic, because I know how yorkies are. They all have running fits, as I call them. They need room to roam somewhere without being tethered. I know that wasn't your question.
Others might not agree with me. As far as rescues, most rescues do require a fence and that goes along with a home and they do home visits, too. I can't say they all are that strict though. You'd just have to read each one's requirements, because they do vary somewhat.