While the Alaska Highway is better than it used to be, there are still sections that are unpaved.
The only surface that scared me, was a short section of road just outside Whitehorse, which was being resurfaced with a layer of 2 inches of sand laid over a thick, hot, coating of oil. Somehow, I managed to skate over this. But if it had been a few feet longer I'm pretty sure I'd have gone down.
I imagined the Whitehorse highway maintainence engineers coming to work that morning, and finding that no life threatening motorcycle accidents had happened in a while, set about trying to remedy that situation. If they could take out an American rider, so much the better!