I've made three trips on the Alcan, twice southbound and once northbound. Never in an RV however. Last time was southbound from Anchorage to Tallahassee, with 26' U-Haul truck and a Kia on a trailer - does that count?
As others have said - whether you want to attempt this trip is entirely driven (see what I did there?) by your desire, thirst for adventure, and ability to deal with the unforeseen. There are indeed miles and miles of "miles and miles". There are also miles and miles of some of the most spectacular scenery and wildlife I've seen anywhere in the world.
It's a long trip. It's an expensive trip. You may see snow in mountain passes any time of year. Services on the road are (at least as recently as '02, my last run) few and far between. But if I had a rig I trusted and a month with nothing else to do? I'd be on the road in a heartbeat.
If you're even only slightly seriously thinking of the trip? First thing to do is pick up a copy of "The Milepost". This is the travelers bible for western Canada and Alaska traveling.
https://www.themilepost.com/