Good luck to Sjaak, I'll be following the ride report as well.
I watched the sled/trailer build and to me it doesn't seem sturdy enough with the decal covered plastics for walls. A curious 1000 pound polar bear would break into that in no time. It's not like you can escape from the sled and take off running, I hope Sjaak brings along some form of defense from a bear. Something like mace, cattle prod, Desert Eagle, you know, something to get rid of a hungry bear.
Other than that, this is going to be an epic journey.