There are radiant heating pads now that eliminate the chill you get from the concrete slab. That would really be the way to go in a home like that. Radiant heat paired with solar.

That's tough when you don't have room to gather. We've never lived in a home we could entertain in until now. Even our bungalow was sectioned off into small rooms. A garage is a good alternative! You can do a lot with that space.