On the vehicle front, we lived at 7,200' for a while , where the temperature would freefall into -30F to -40F as sunrise approached. My most expensive learning lesson was to change to a 5W motor oil in the winter. I left 15W40 in an old Chevy Blazer and trashed the engine.
Engine block heaters are the bomb.
Even when I'm driving around / near town, I dress for walking for help. I keep a pair of Goretex lined boots and an insulated Carhartt jacket with a knit hat and insulated elkhide gloves in the back seat of my Jeep. Survival gear was simple - keep a full set of camping gear in your vehicle, including 0°F sleeping bags.
I've never been stranded in my vehicle but I have woken up to impassible streets, snow drifts filling the doorway and a general inability to go anywhere for 2-3 days except on foot. The mountain town I lived in had one road that led to civilization. The locals had stories of the road being closed for a week at a time and stores (including fuel) not being restocked. The highway closed kinda regularly for a part of a day and if it happened on a Monday, the shelves at the single grocery store got a little thin of perishable goods until the highway opened. We didn't go "full prepper" but we kept bread in the freezer and a modest amount of boxed milk in the pantry.