It occurs to me that if you are going to be dependent on an automobile and its fuel supply for heat, you would be better off buying the samllest gas powered generator that is capable of powering one of those oil filled space heaters. With this setup, the generator can be placed outside of the car and the heater inside with just the power cord running to the generator. The oil filled space heaters have no glowing elements that could start a fire and they have thermostats for heat control. They take up the space of one passenger, and the small generator will use a lot less gas than any regular automobile, can be located downwind away from the car, and will not screw up your automatic transmission by running the engine for long periods of time without moving.

Be sure to have some sort of petcock installed in your gas tank so that you can refill the generator, or have a siphon that can get past the anti-theft fill nozzles of the newer cars.

Good luck!

Bountyhunter