I am not an expert, but battled similar problems in a similar house in a similar climate.
i) If the basement is unfinished, insulating the rimjoist is cheap and fairly easy; you can use insulation board and/or sprayfoam.
Even more than insulation, plugging draft gaps around the rim joist and elsewhere is important; many older houses will have perforations from past cable, plumbing, etc.
ii) Get furniture, books, etc, in away from the walls to allow air circulation; ex. wooden blocks to space out bed headboards from the wall.
iii) Do you have, or could you put, zone control on your propane baseboards to give a little heat in the problematic bedrooms?
iv) Moving air to and from the area with the stove would help, although it can be difficult on a single level house.
Theory says you should push cold air towards the stove; my experience was better pulling warm air from the stove. Either way the air flow needs a return. Eyeballing your nice stove, it maybe a little undersized to heat the whole house?
v) If you reside, adding insulation board underneath the new siding, properly installed, will likely help alot, as long as the insulation extends down below the problematic spots. It was transformative in my similar past house. But you need to avoid creating a condensation/frost layer within the wall causing hidden rot.
vi) Can you tolerate doing without the humidifier?
vii) You could possibly put insulation board on the problematic inside wall and drywall over that; besure you achieve a vapour barrier so you do not get condensation between layers of the wall.
viii) You may find you 'chase' wet spots around; solve one, the next coldest spot becomes the new condensation spot.
good luck. Doug
