Remember, there's the trip back home.
You put entirely too much faith in late Neolithic/early Ironage people spending 8 full years sweating brown bears and polar bears just to pick up some hunks of iron.
Think of it as a question of survival. If everyone around you has Iron, and you don’t, you are going to get destroyed.
The idea of taking a dogsled from Alaska, all the way over the Mountains, across the Rivers, etc, doesn’t make any sense to me, not with hostile native tribes who already live there.
Yeah, 4 years is a long time, but more sensible then 6 weeks.
What trip back home? They relocated to stay.