Thinking house thoughts again. Primarily the roof. I know that the bastard is really poorly insulated, since I've actually seen it. The good part about that is that it's probably not rotten, at least in that section, because it has enough air circulation getting to it that it doesn't retain moisture. The bad part is... well, winter.
The roof just isn't good. Roof technology has improved by humps and scads since this house was built in 1922. Knowledge about materials, venting, insulation... it's all there.
R38 roof (12" fiberglass batts)
Code requires that all woodstove and wood fireplace chimneys must extend at least two feet above any part of the roof within ten feet; masonry chimneys must extend at least three feet beyond the highest point.
Roof pitch, mins & max