The vestibule looks great. That will help a lot.
It will be cold, not like you know it in Decorah, but you've been to ND before, I'm sure.
I like a lot of pairs of wool socks... varying weights. And two sets of outergear... boots, coats, mittens, hats, scarves... one to wear, one to dry. Is there an outlet in the vestibule?
Honestly, I don't miss winter that much.... but I do miss the first snowfall. And the Northern Lights
The strawbales around the perimeter are a great suggestion from Darwin.
Best wishes for a mild Dakota winter.