What would you do if the world ended and you were one of the few survivors left. You and the wild. I would just look for other survivors, look for a gun, and barricade myself in from "zombies"
I would rob vault after vault and create a beautiful garden out of several hundred million in hundred dollar bill stacks, then find a pack of matches and write depressing peotry about how the world wealth was swept away with it's people. Then i would raid pharmacy after pharmacy for various mind-altering substances
I would most likely go to the Doomsday Vault, It's a vault that contains millions of millions of seeds so that in-case of an apocalypse the ones that survived could start civilization all over again.