I would be thinking a gas driven generator, portable.  I have a Honda, not sure of size of the top of my head.  I have ground loupe heating for my home.  I would disconnect incoming electrical line in my box.  Wire in my generator.  Throw all the breakers off, except for what I wanted to run.  Furnace for a while, then the refrigerator for a while, then the well pump, ect.  

I would leave the generator in the garage and run extension cord down to basement.  I have some big size 220 cord, something like you would run a welder with, to bring the power from the garage to panel.  Don't think I would loose to much if any noticeable amps.

Thanks for the idea.  I should check my generator size. 

(I could always just bore a small hole to the basement from my garage and would be only 10 feet from my panel.  So cord length should not be a problem. )