Is this even possible? December in New England?

My advice would be to find a campground that is open with hookups somewhere to the south. I'm pretty sure Western Village in Carlisle PA is open year round. From there rent a car to head north and stay at hotels.
The coastal areas usually stay a little warmer than the inland areas. If you are insistent on RV'ing into the northeast I would try to stay close to the coast. If you hear anything on the news about a classic nor'easter coming .... head south immediately.