My thinking was to get a coal burning stove and stock about 4 tons a year (what I estimate I would have to go through up here during the cold season).

For the retreat, I was thinking maybe a connex box or two full of coal would be a good fallback. Just make sure they are not leaky and fairly secure. 40 tons of coal would last quite a while that way.

Coal Gun Stoker for home

This system looks promising. The local coal supplier described their coal as a high quality anthracite and sized for this system. Seems pretty straightforward. I'll have to look into costs and installation issues.