Last week's story of the Oregon family who got stranded in their car (Dad, who went for help, died before he could find it) got me thinking about what everyone needs to keep in their trunk during the winter, especially when driving through more remote spots in the Rockies.
Outdoor Life has a long and silly (though not intentionally) list of what the emergency car kit should have. First item, no kidding, 3 sets of underwear.
While changes of underwear would be nice, here's more practical advice:
a warm jacket
a sleeping bag
some food with a good shelf life
something to start a fire with and, if you have it, a camp stove.
I think it's less important to be ready for a week than ready for five or six hours. Two weeks ago my car konked out between Alma and Fairplay. Not exactly remote. But it was 9 degrees out. It took the tow truck 2 hours to get there. I was glad I had extra clothes in the car.