I don't RV in Alaska, but spend a fair amount of time (when I'm not in Ewe-stun) on the roads up north.
I would think a 5ver and pickup is the ideal combination. Find a campground, drop the 5ver, drive the truck on the backroads, say Hatcher Pass, then back to the 5ver for a comfortable evening, drinks, and a campfire. Most "campgrounds" will have at least reasonable access for a 35' 5ver and there will be quite a few boondocking spots that will take it as well. Helps if it has some good ground clearance, but not an absolute requirement.
It's nice having a vehicle (such as a pickup) that is separate from the main RV to use to ram around towns and/or get back into some nooks/crannies.