We went up the Alaska Highway summer of 2015. Ditto the comments above, especially the road condition between aptly named Destruction Bay and the Alaskan border. We took two stones to the windshield, and numerous small stone hits in the coach from high-balling (well over the speed limit) big rigs headed in the opposite direction. You can only pull over to the right as far as possible and come to a near stop to attempt to reduce damage. If you see a big cloud of dust coming towards you, move right and slow down as much as possible.
We also took the Ferry system south to Bellingham, Washington after our visit to Alaska. I would suggest you take the Alaskan Highway north to experience the towns, people, sights, museums, culture, and history. If we were to go again, we would take the Ferry both ways to avoid further damage to the rig.