Tony, any time you head up into the wild north it is recommended that you take additional cans. I would recommend at least 1/2 of your vehicles capacity at a minimum. For example, I take 2 5 gal cans in addition to filling up at a station up there. My truck holds 100 litres, but if you get stranded and need to run your engine for heat, running out of gas could be life threatening.
If you are worried about space, take some whisky in place of beer (another bonus is that it doesn't freeze.