However, if some tales of survivalist stockpiling are to be believed, our nutty neighbors have enough of the social lubricant squirreled away to hold the most epic end-of-the-world-party of all time outside of Edgar Wright's social circle. It might not be practical, but who needs practical when you and everyone you know is doomed to die from radiation poisoning or cancer?
This group has a primary concern with maintaining some form of legal system and social cohesion after a breakdown in the technical infrastructure of society. They are interested in works like The Postman by David Brin, Lewis Dartnell's The Knowledge: How to Rebuild Our World from Scratch, or Marcus B. Hatfield's The American Common Law: The Customary Law of the American Nation.
To me, the best option is to store emergency food. How much? If you have none, store enough for a few days. If you have enough for a few days, get enough for a week. How much you store depends on what time frame you think you're at risk for having to be completely independent. The early settlers of the southwest liked to store enough food for a whole year and still do to this day!