Slowing probably won't work given there is a 400-500km drive ahead. Anyways, I'm not that experienced with snow but have a couple of experiences and now I'm carrying chains during winter. Below is about 35mph in icy conditions with KO2s.Or if she slowed down. I've driven that road and it's ez to get lulled into driving to fast for the conditions.
I now have the engine and transmission from that truck sitting in my garage, haha. Engine has been torn down and refreshed and is sitting on a stand waiting to go in my 03 if the need ever arises. Likewise with the tranny.