If you start with fresh tourances in Missoula you should be fine up and back. We stayed at the hotel across the street from the NAPA in Dawson.
Montana has tons of dirt roads. Start riding them and get comfortable. I took our low experience guy down the Montana farm roads to get him experience and skill. He crashed and his brother and I almost crashed on a spot where they just fluffed up the gravel. We were a mile from pavement. The sign said road equipment working but it was after 5pm so we thought we were safe. The gravel was loose for 8 inches.
AK and all those roads are much more scary and dangerous at your computer than actually there.
I went to Deadhorse. The bad parts of the roads give you warning. Take it easy and enjoy. We met a guy on a cruiser who crashed but his front tire was bald/slick.
Ran into a guy from chicago who went to Inuvik. He was on a GSA and said it was no problem.Top of the World