I'd even pass on the tire deal.
You're going to Alaska. Great trip...hope to make it someday in our coach.
Big thing many don't understand about Alaska...I drove to Anchorage in 1974. 1100 miles on the AlCan highway. At that time, less than 10% was paved, the rest was dirt. It was really GOOD dirt, but still dirt. When I drove home in 1978, pretty much the same, although the paved stretches through towns had gotten a bit longer. At that time, there was one stretch of the AlCan that was 98 miles between two buildings. Not towns...BUILDINGS. That's a lot of wilderness :) You had a mandatory "pack list" that got inventoried by the police before you were allowed to get on the AlCan...flares, spare, first aid, tow strap/chain etc. I think they even required a spare carb back in those days, though they were starting to soften up on that requirement. Flares were essential because that is absolutely the EASIEST way to light a fire, even with wet wood. Most folks would coat all of the weather stripping around doors with a heavy coat of vaseline to help seal against dust.
Now, the whole thing is paved. Trucks travel that highway all the time, 12mos a year. I'd carry an unmounted spare, which any truck tire service would be able to mount roadside for you.
Jim