This is awesome. I'd love to do this, but just don't have the guts to pull the trigger. You Sir, are inspiring. Best wishes and prayers are headed your way.
One idea for heating, since you'll have electricity, would be to use the rolled up in-floor heating materials. The benefits would be that it keeps your feet warm first. And if you're like me.....you're finished
if your feet are frozen.
The other benefit is that heat rises, so a heated floor is the best place as opposed to a vent on the roof.
This exact product is not a recommendation, just a Google search;