Originally posted by Limited Instruction Set:

I put a campfire right outside one door, bed next to wall inside, no problem.
Not my favorite solution, but I've only just started playing.

Campfire on the bare ground inside the building, make a chimney around it up to the roof to channel smoke, make a gap with pillars to let the smoke out, put a roof on that. At the bottom of the chimeny do make a total frame around the fire so you can't accidently walk into it.