You know what would have been kinda fun? Founding a town. With enough caps you can hire workers to build/repair some structures, tap into the power and water lines, then attract some venders and whatnot. Build an armory and stock it up to fight off raiders, maybe buy some slot machines and set up a casino of your own. All that stuff would have been something actually interesting to dump money and supplies into developing rather than just tossing it all into my infinite junk drawer to gather dust.