Living aboard in areas with hard winters is tricky, especially if your boat is not insulated. Condensation in lockers can damage wood, and cause rot and mold. To keep the interior dry, it's necessary to get rid of the moisture generated by cooking and breathing. To dry the space out you need to allow air from outside into the cabin, and then heat it. The heat won't stay if your boat isn't insulated, but winter isn't the time to add insulation, it's better to wait for a drier, warmer season. If you try and use adhesives in cold weather, materials won't bond to the hull.
In winter, we sleep in the saloon and close off both the v-berth and quarter berth (with heavy curtains). It is easier to heat a smaller space. For outside lockers, insulating the walls they share with the main cabin (if any) and leaving them cold is the best option to prevent condensation.
When we cook, we crack open a hatch to allow the steam to escape. We don't have room for a fan so this is our best option.
Hull. The best hull insulator is closed-cell foam that is bonded to the bare hull using self-adhesive or contact cement. Insulation must be sealed. Other options include a Reflectix and polyethelene foam sandwich (reflectix > polyethelene > reflectix) with each layers held in place with polyurethane caulk.
Bilge and floor. For the bilge area, keep it dry and cover the floors with carpet as insulation.
Mast. As is, our keel-stepped mast is a huge heat sink. It's a good idea to insulate it by wrapping it with reflectix, even if it is unsightly. The Frugal Mariner covered theirs with a layer of flanel-backed vynil, attached with velcro.
Windows: The windows on our boat are another source of heat sink. In the saloon, we have six 8 mm acrylic windows. We have plans to install a layer of thin plexiglass on the inside with an air space between it and the acrylic for insulation. The plexiglass would sit over an epoxied wood frame, onto which we can slide curtains for added shielding from both the cold and curious dock neighbors.