Spam and fruit cake have a VERY long shelf life. Use your BBQ grill with extra propane tanks to boil the water after the expiration dates.
Auto load 12ga shotgun with slugs as well as buckshot ammo. Hand guns of 45 cal or 9mm and lots of ammo.
A Bible to read while you wait for the living dead to descend on your castle.
They have a long shelf life because no one actually eats them. Therefore the ultimate longevity of fruit cake has never been tested.