"I'll be in a 4wd truck camper that isn't overloaded so shouldn't have an issue. My plan is to average about 100 miles per day with more days allowed for stopping and taking in the sights."
FWIW, the Denali Highway is listed as 135 miles....the last time that I drove it for recreation (not getting from A-B fast, not hunting, etc), I spent two nights on the highway, departing from Paxson late morning, and getting to Cantwell late afternoon.
It's worth the time....and if the road is exceptionally rough (which I've seen several times), 25 mph (with a load/trailer) is a good, aspirational target.