Firearms instructor and survivalist Colonel Jeff Cooper wrote on hardening retreats against small arms fire. In an article titled "Notes on Tactical Residential Architecture" in Issue #30 of P.S. Letter (April 1982), Cooper suggested using the "Vauban Principle", whereby projecting bastion corners would prevent miscreants from being able to approach a retreat's exterior walls in any blind spots. Corners with this simplified implementation of a Vauban Star are now called "Cooper Corners" by James Wesley Rawles, in honor of Jeff Cooper. Depending on the size of the group needing shelter, design elements of traditional European castle architecture, as well as Chinese Fujian Tulou and Mexican walled courtyard houses, have been suggested for survival retreats.
Here are just a few choice gems from The Prepper Journal's 11 Ways A Condom Can Save Your Life: starting fires (they're great at protecting tinder from moisture), hunting for food (sexiest slingshot ever!), and transporting up to two liters of water (yes, rule 34 applies; no, we won't provide the link). They also make serviceable stand-ins for rubber gloves and can be used to protect the muzzle of your other essential survival tool (killing it right now).
Modern-day survivalists aren't generally regarded as the most sane people on the planet. A quick look at any one of the disturbingly common and frighteningly thorough shopping lists they post online drives home the fact that anyone who self-identifies as a "prepper" most likely went off the deep end a long time ago. Sure, it's fine to keep a few extra cans of food and cases of water around for an emergency, but if you start adding body armor and butt paste to your stash, you might want to tell George Miller that it's time to see other people.
The wise outdoorsman always has a multitool with his survival gear just in case. They’re light, affordable, and in the case of the Leatherman OHT they’ll put the venerable Swiss Army Knife to shame. The OHT features needlenose pliers, spring action wire cutters, a high carbon blade, a serrated edge, a can opener, Phillips screwdriver, bottle opener and myriad other attachments.
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!