we came down the highway this spring. I wouldn't plan on making 3 -400 miles every day. Depending on your driving experience, you're going to be doing a lot of mountain and narrow road driving that might slow you down. On some of the pavement in the northern parts we were down to 25 - 30 MPH. If you get a breakdown most of the repair places are backed up 7 - 10 days. If you're going to blast through Canada and the rest of Alaska that fast without seeing anything, then why not fly to Anchorage or Fairbanks and then rent a MH go to Denali? It would be a lot cheaper.
Bill