The outdoor activities are ludicrous
Some of the only US rainforests are in Puerto Rico, which not coincidentally is now home to El Monstruo ("The Beast"): the longest zip line in the whole wide world, spanning almost 7,500ft. After recovering from that, the move is to boat, swim, wade -- and dodge bats in -- one of the 200 caves in Rio Camuy Cave Park. At their deepest points the caves are pitch black, which is why I got to wear one of those kick-ass mining hats with a built-in light.
When you need a breather, hike a trail or find a cliff to rappel or jump from in these same parks. Condado Beach, at the island's tip, is a haven for every water sport ever -- and just as importantly, for every beach bar to hit afterward.
Do absolutely nothing in total bliss
Here's where to fully check out: Playa de Guanica. It's palm trees, grass huts in the water, mountains all around you, and proper cocktails at Copamarina Beach Resort & Spa. This beach is also the launch point for a ferry to a tucked-away spot (cleverly) called Gilligan's Island. It's not precisely where the S.S. Minnow went down, but aside from locals playing music and BBQ-ing on the banks, it has the same feel. The entire hidden island is a labyrinth of water and mangroves that you can stroll, swim, or just float through; if you drift deep enough you will be sitting on your own private little beach that, according to one of the locals I met there, "you can be totally naked on and no one will even see."