To the OP....sounds like a good plan to address possible risks.
In 20+ trips since the early 70's (although none recently meaning past 15! years or so)...
- I've made quite a few to/from Seattle/Montana area, and a few to/from Denver/Dallas, etc that were measured in hours, not days (running from 72-ish to 100-ish)...oh to be young again;
- I've had one memorable trip in the early days where Puget Sound to Los Anchorage took more than 2 weeks where anything you can think of went wrong: (gaskets and seals lost, flat tires, busted headlights,"what do you mean there's no fuel in FSJ until tomorrow?") (FWIW, this was with a commercial truck!?!)
- I've had trips (see above for the "hours not days" trips) where NOTHING, absolutely NOTHING went wrong other than a couple of "I'll take a two hour nap" periods turned into 3-4 hours.
- I've had a trip or two where a fire, a shovel, and the local provincial authorities (this was way back in the day) conspired to really mess up my travel plans; :)
- Also back in the day, after the immediately preceding trips, I said to myself that "Boy I'm glad it's raining, beats fighting fires"....a few hours before I put the deuce and a half off the road in the mud. :(
One of these days, I'll take another Alcan trip, but I do miss the old days.