The Milepost tends to keep pretty up to date on which stretches of road are bad, so get a current copy. Don't be surprised if you come back with a cracked windshield. I went up with one and came back with one, but way more cracks. I saw big rigs going 5 mph over some of the potholes and frost heaves and was glad it wasn't me, seems like it would take forever and also some of the fun out of it. OTOH, they all had nice places to rest at night and I didn't so much. It's a big trade off, but lots of big rigs do it every year with no problems, at least it appears to be that way.
I did meet a guy pulling a big fifth wheel in Teslin and we talked, since we were from the same area, and he told me he would be glad to get home, as he was tired of pulling the thing. He said he would never do it again, but others do it every year.
I will add that most of the highway is as good as any in the Lower 48, it's just the few bad stretches that will gitcha.