Cruise America is the biggest I know of. OK if you don't mind driving a billboard. Closest pickup yard looks like Islip, Long Island. Get yourself a good GPS. Going to need it in the Northeast. CG availability will be hit & miss. Generally not much problem Sunday to Thursday. Could be problems Friday & Saturdays especially in high demand areas. Lots of CGs have a few no reservation sites. Get there on Thursday & stay till Sunday.
Driving anywhere near the major cities is no fun at all. Aggressive drivers & poorly signed roads.