If you can be in Skagway when no cruise ships are there it's a great place to explore. Agreed with the above post that driving to the Chilkoot Trail is a must and try walking it if only for a very short distance. You'll have a better understanding of what they went through.
The drive to Valdez is awesome and again, seek out the parts of town that tourists rarely see.
We enjoy the drive to Homer and Seward - but not on the weekend! Alaskans are campers/fisherpersons, too, and that road is packed and dangerous on the weekend and holidays.
Denali National Park and Teklanika campground, in particular, are real jewels. We spent 10 nights in the park our last trip.
Alaska is amazing but don't forget about exploring Canada and the Yukon, too. Some places are even more beautiful than Alaska.