It's funny how 'Life' experiences quickly come to mind so all I can offer are some suggestions based on 'opportunities' we encountered in similar cold climates , and I'm already pretty confident you've considered these and/or have something similar...but still worth noting:
*A good jump starter which also offers ports to recharge a cell phone.
* If you wax your van now, ice & snow becomes considerably easier to remove (would do the same on headlight & brake lights).
*New Wiper Blades, and a bottle of de-icer (i've used this stuff on the side & back windows, headlights, brake light housing, as well as side mirrors) to help with visibility. I keep a bottle of Prestone Ice & frost shield in my back box.
*Since you anticipate severe cold, I'd use a silicone spray on your door gaskets so they don't freeze to the body & also spray your lock tumblers (doors, padlocks, thule box lock, etc) - This is also why I keep Prestone de-icer is in my rear box >> once I was unable to 'open' any of the doors...
very frustrating when you aren't armed with an immediate solution & don't have easy access to warm water.
* As a precaution, I always keep stormproof 'wind' matches along with shredded magnesium (gets almost anything burning) - I also have a 1lb propane torch to satisfy my occasional pyro tendencies when all else fails!
*Rechargeable LED Road Flares Emergency Lights would be a useful addition (supplementing Road flares since these last longer). I have set of these and have to say they are extremely bright & work well.
https://www.amazon.com/gp/aw/d/B098Q...af9d635d0&th=1
Sure sounds like an adventure. Safe travels & Hoping your trip exceeds all your expectations!