I think you can power the camera with an outboard battery. I have to find my book with the wiring diagram of the jack.
If so, when it is COLD, you can keep the battery under your jacket with a power cord to the camera. Then it will only be the question of the lube in the low temp.
Absolutely, put the 9 volt in your pocet and run a cable up to the camera body.
Also, post some of the aerials when you are finished this initial project