You'll have no problems with that setup in BC/Yukon and like you said just pick up an extra jerry can for the run up the Dalton if you feel the need. I didn't get the greatest gas mileage with the Tenere and only used my 1 gallon of extra on the Dalton. Headwind out in the tundra after going through the Brooks Range really affected my mileage into Deadhorse. Plenty of places in BC/Yukon to get gas, my only advice there is if you go through a small town with gas and feel like you should have got gas, don't be afraid to just double back and fill up, I think you will find that you end up filling up when half full or quarter full most of the time vs pushing it to the limits. Depending on your definition of "secondary roads" your experience may very, i.e. taking the Campbell Hwy. Common rule is if your buddy has to use your extra gallon of gas in addition to his own at any time he has to buy the beer that night. Safe travels!