Welcome to the club!
I would definitely have some radiator hose repair tape, a gallon of premixed coolant/distilled water, basic tools, a KNOWN GOOD spare tire, spare belts, some spare bulbs (headlight/taillight), wiper fluid, and either a CB or, if there is cellular coverage, a cellphone. Not sure what the coverage is up there, I know in my last pass through the Great White North, cellular coverage was not so hot, but it's been a few years.
The biggest consideration is what you can do on the side of the road - no point in bringing a ton of stuff with you if you won't have any means of using it unless you are in a garage.
Got AAA or the equivalent?
As far as the tune-up: spark plugs, check the wires, all the fluids (oil, differential, transmission, brake, coolant), thermostat, check all the coolant hoses. Make sure your cooling system is in tip-top shape and well-bled. Rear defroster work?