We traveled the road in 2006 and it was mostly paved. There were some frost heave, but they are usally marked with flags on the roadside so you know where they are. There were some gravel streachs, but they were usally short. We traveled with a caravan with 19 rigs, and no one had any rock damage. If you are planning to travel the Cassair Highway, be prepared for a lot of gravel, about 26 miles or so, was pretty rough in '06.
Remember one thing about Alaska, there are four seasons, almost winter, winter, still winter and road construction.
My advise, Take the trip, take your time, and you shouldn't have any problems ... Paul & Kathie