Those are nice questions, and unfortunately I don't have any answers.
We went in 2019 with a 31-ft C Class and pulled a Honda Accord on a tow dolly. No issues other than a crack in the windshield that insurance took care of, and a couple tires.
I hear the roads have gotten better since then but your best bet is to take it nice and slow so that your suspension and tires take less of a beating.
British Columbia deserves just as much time as Alaska does, and we enjoyed the whole 10,000 miles to and from Chicago.
There are plenty of gas stations and amenities of all kinds, and perhaps the most eye opening thing is that there are all kinds of people going to alaska. Bicycles, motorcycles, small cars, minivans, small RVs, Big A's, etc. Her worry we had, they were doing the same thing and we all made it.
Have a great trip!
