If one is truly going 4-wheeling, #1 should be another driver in another vehicle appropriate for the trail.

And the emergency food should be something that is not only highly nutritious and keeps forever, but is also nasty-tasting. The reason is that it should always be there and if it tastes horrible to you then odds are that it will be there for you when you truly need it. Anything that is even a little satisfying is likely to get snacked-on at some point and may not be there when you really need it. This is what the Red Cross teaches in their Wilderness First Aid course.