I don't think the effort involved with what you are describing is worth any gains you may receive. You would be better off with the honda engine block heater pluged into a timer that turns on for say 1/2 an hour before you leave the house.
However, if you insisted on the heated garage idea, I'd just build a hoop-house and park the car in there. These cheap greenhouses can get well over 80 degrees in hard winter climes, and parking the car in an actively warm environment would reap greater rewards, I think.
Look at the picture 3/4 of the way down this page:
http://www.westsidegardener.com/howto/hoophouse.html
Just pull away the plastic, drive in, and close it up behind you. You can make these super-cheap.
However, if you insisted on the heated garage idea, I'd just build a hoop-house and park the car in there. These cheap greenhouses can get well over 80 degrees in hard winter climes, and parking the car in an actively warm environment would reap greater rewards, I think.
Look at the picture 3/4 of the way down this page:
http://www.westsidegardener.com/howto/hoophouse.html
Just pull away the plastic, drive in, and close it up behind you. You can make these super-cheap.