Clev is right on about heat.
I am thinking for now, that I would use a NON-built-in 12V electric defroster just set up on the dashboard. Also, I would have a seperate 120V ac heater that I could pre-heat the car with in the garage off wall power.
EDIT:
I stopped by the thrift store today.
They had a vibrating massage seat cover. You know, one of those things that looks about like this:
What was interesting is that the power supply for it was a wall-wort 12V DC adapter and it had a HEAT feature.
Just imagine, a Geo with heated seats..... such luxury!
I tested it at the store, the heat feature was pretty mild. Still, on a ten minute drive, it might not be bad to have.
They wanted 26 bucks for it. I passed. Maybe if it's still there on half-off days, I will look at it again.