Cueva del Indio is a bit off the beaten path. Locals seemed impressed that we had been there and tourists looked at us confused when we mentioned it. Though it came up as a recommendation on a number of travel sites, I can see why tourists might pass it up: we took windy roads much of the way there (I kept promising my husband we were only 10 minutes away) and Google Maps didn’t seem to have any idea where we were going. However, you’ll eventually see signs for Cueva del Indio, and you’ll even pass a few beaches on the way (such as the black sands of Playa La Boca).
I consider PR to be a great “bang for your buck” destination. Not only can you find a reasonably-priced flight, but there’s less planning needed if you’re traveling from the continental U.S.; you don’t need to bring a passport or exchange currency, and most locals (at least around San Juan and other touristy areas) speak English as well as Spanish. At the same time, you get a true cross-cultural experience and there seem to be endless places on the island to explore.