An observation from regular annual trips to and from Alaska over the past 7 years and irregular trips over the last 40+ years, the Class A motorhomes do not slow down enough early enough when they encounter the frost heave and road damage sections, but they eventually learn.
Road damage and frost heaves can be anywhere in the north and are most common between Whitehorse and Tok. The Yukon roads are fine with wide lanes and mostly wide shoulders. When you see the red flags stuck on the side of the road slow down. Some are leftovers after the problem was fixed and some are not. It is the 'are not' that bite.
There are thousands of RVs that travel to and from Alaska every year, many of them Class As with toweds. North of Dawson Creek just plan on 350 miles a day or less, and average speeds around 45 and the trip is easy. You will almost always be going up or down or around.
This past August all of the historic bad sections were either under repair of mostly fixed. Winter will change some things, so expect some repair areas, some construction, some delays. Drive at the posted speed and all will be fine.