You may want to visit NYC for a couple of days basing from a Hotel, and then catch a commuter flight to another city, Boston, or Hartford, and rent the RV there for the remainder of the trip.
Edit add. The more I think about it the more the idea of flying in through JFK seeing NYC from cab and hotel, and then flying to Boston makes sense. You can rent the RV there, and make a circle, down to Cape Cod, then Conneticut, over to the Catskills and upstate New York then head back East through Vermont, New Hampshire and Up to Bar Harbor Maine, before catching I-95 back to Boston, turning in the RV and flying home out of Logan. The RV part of that is a workable, but active 2 week circuit.