The stories of alcoholic beverages historically being safer to drink than unfermented ones are apocryphal at best; however, as any 17th-century sailor would tell you, the addition of some spirits to potable water that's been sitting around for too long will make it much more palatable. Liquor distillation was originally invented in part for medical purposes, and alcohol can be used as a solvent to dissolve medicinal herbs -- and also to knock out patients during good old-fashioned fallout-shelter surgery. High-proof alcohol can be used as an antiseptic, and it does a great job of cleaning wounds and preventing infection.
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.
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!