Assuming Canadia is still selectively denying Americans access to their country this fall, weather is not your biggest concern driving there.
You're not going to take the ferry in Sept/Oct. Look it up. No ferries to mainland AK after July/Aug. And no sailings out of Bellingham after Sept and only to limited southern AK ports.
If you went in the summer, it would be about $3500 each way to Valdez or Whittier, cheaper to Haines if you're not locked out of Canada.
We took the ferry from Prince Rupert to Haines once. Awesome experience. 36 hours was enough, 3.5 days from Bhm to Haines and another sailing to Valdez or Whittier would have s ucked.
You could barge your truck and camper up and back and fly in. Barging vehicles south is cheap, north is alot more but I haven't shipped anything by barge or steamship since 2014.
But your thought process for the trip makes absolutely no sense anyway. Whether you're going to Anc or Fbks (presuming you're visiting at JBER Wainwright or Eilson, you'll be in a city with hotels. You're afraid of road conditions so not sure how it would be different driving from Anc to Fbks or touring around the state from either location (the reason for the truck and camper, right) in early winter. Plus, there's virtually no tourism , nothing open, no leaves, no fishing, no sightseeing in the Parks etc etc.
Even most hunting seasons are over. I love recreating all seasons in Alaska, but there's nothing to do except scenery and cold weather in the fall and spring.
What's the point of the truck and camper if you're afraid of snow driving and going in an off season?
Flights are cheap in general now and hotels and rental cars are also cheap in the off season.