Go down to Mexico, get some guns, and chill in Costco. The Costco's by Tijuana have massive bars on the windows, the windows themselves are small, they sell pretty big guns in there, and it has a large supply of food. There are giant metal gates that close every entrance, and there are areas on the roof to camp out and kill some zombies. Not to mention that Tijuana has the most ruthless crime bosses in the north western section of the city, they would send guys down to go raid places and probably kill a ton of the zombies in the process.