Ben that is great news on medical school and a brilliant idea for cheap Boston rent to boot. As Ebb said, I think insulating the hull is the first order of business, and now is the time while you have things all pulled apart.

I know there are some crazy folks around here that winter over in Portland. They shrink wrap their boats, which seems like a good idea since you won't be doing any sailing AND you won't have to shovel snow off the decks. Plus, then you could install some sort of temporary solution over the forward hatch which would leave more badly needed room below. (?)

Maybe you can find some winter live aboards down at Spring Point Marina in South Portland - there are usually a few. Talk with them and get some firsthand ideas from them - or even take a trip to Boston.

Also, maybe check out Kurt's forum SailFar.net, you'll probably find some winter live aboards there. Good luck! Exciting times!