For car storage, I would want something like a 0 degree sleeping bag and lots of water. I might not want to cook anything, but it would be nice to have a way to heat things up, so some chem heat reactors would be nice. Cans of spanish peanuts have lots of food energy in them, and seem to store well hot or cold. Spam also seems to do well in vehicles. Packages of Ramen noodles seem to last forever and also seem to do well regardless of temp. You've got all that space, you should be able to capitalize on it better than just a couple bags of jerky and some candy. I could imagine packing supplies enough to last a couple weeks in some of the worst conditions, with the ability to signal rescuers really well, and still not be overly encumbered.