I just got back from my Alaska trip, the first I've made since '67 and '68. Compared to back then, the Alcan is a breeze - the difference is unbelievable. A few spots under repair and the 100 miles right before the Alaska border were full of frost heaves requiring a lower speed, but over all it was a walk in the park. I spent about a month on the Kenai visiting my old home, plus I did Seward and Homer. On the way out I did Valdez, Haines and Skagway. Got stuck in Skagway for a couple of days because of a rock slide on the Canadian side that closed the highway, but I could think of a lot worse places to be "stuck" for a few days.
I did park at a friend's house while on the Kenai and I did mostly dry camping on the way up and back, so my camp fees were kept to a minimum. I also didn't do any of the tourist type things like tours, ferry rides, fishing trips, etc. My total cost for the trip of approx 11,000 miles was about $5,000. That breaks down to $3,000 for gas (I got about 17 MPG and used 687 gal), food was about $540 (just me), camp fees about $550 and Misc expenses about $1,000.
Hope this helps others who might be planning a trip.