Hi David,
Well I ran up to Flagstaff for the night and this morning it's -5 outside and 55 inside so so far so good
The heater works via an air to air exchanger and the cabin air is being recirculated through the heater...no outside air is drawn in for that part (for example right now I have the heater drawing in the air from behind my couch and then exhausting it out the front of the couch). For the combustion part only outside air is used, it's drawn in from underneath my van and then exhausted out the bottom towards the rear of my van.
You should definitely be able to use a jerry can with this. I'm not sure if you might run into any problems with air bubbles in the fuel line from when you disconnect it and reconnect it but other than that i can't think of any reason that wouldn't work. I i had actually thought about putting the fuel line in a jerry can before i installed it just to test it out.
Jeff