If you are gonna drive in the deep freeze:
Have at least one blanket or sleeping bag for each passenger.
Have spare gas.
Have hot tea. Even hot water will do.
Have a flashlight (or three).
If you have a ham/CB/FRS Radio take that too.
Keep someone informed about your trip, call them when you arrive
If you are stuck, do not go looking for help.
Stay on main roads.
That stuff might save your life.