A fireplace in the boat is a great thing. You don't get to imagine it until you see it and try it. I don't have experience of Alaska winters, but in New England autumn and New Zealand winters, it did work great on our boat. We have a Newport By Dickinson and burn mostly wood in it. Talking about the cost of the fuel, it is not an issue in our case: we burn drifting wood that we never failed to find in abundance along the shores. It is well dry, smells great and heats you for free. The only problem is that it contains salt and tends to leave rust stains in the heater...
Next boat we will stick to a solid heater fuel, but bigger, possibly in cast iron or thick aluminium with radiators for the cabins.
Anyway in case you winterize in a very cold place you will have to stick to a jetty or a marina. Except for Antarctica, but then you can bring coal!