My comments are not bus related, but motorcycle related. I rode the Alaska Highway to Fairbanks on a BMW R100GS Paris Dakar motorcycle in 1992. I was amazed at how good the road was in most places. There were construction zones, but I don't recall having rocks thrown at me and feeling like I was in constant danger. However, I have not done it in a bus, so don't know what you might experience.
After riding the length of the Alaska Highway, I returned from Fairbanks to Tok, AK, and then took the Top Of The World Highway to Dawson at the base of the Dempster Highway in Canada. Top Of The World Highway, best I recall, was a fair bit rougher than Alaska Hwy. My memory of that road would tell me not to travel it in a bus. Then I took Dempster Hwy north to Inuvik so I could cross the Arctic Circle. My trip was less of a sightseeing trip than it sounds like you might envision. I rode 10,770 miles in 15.7 days. But I was amazed at the beautiful scenery and the friendliness of the people.
I wonder why the guy who told you all this bad stuff went back for seven years in a row. Sounds like he's a slow learner. When I got to a gas station at Eagle Plains (or maybe it was Eagle Creek) on the Dempster Highway, I saw two other riders going southbound. I asked them how things were the rest of the way to Inuvik. One said, "Don't go." The other said, "Turn back."
Well, that wasn't acceptable answer for me, so I ignored them and on I rode. I think you take care with what you do, and you know your limits better than anyone else. You race motocross, so the "doom and gloom guy" may be telling you about Alaska from his perspective and it might not correlate with what your experiences will be when you go. I say go.
eric faires
huntsville, TN