Stopping in Puerto Rico was one of the best things that has ever happened to me. Definitely one of the best things you can do is take the horse back riding tour at Rancho Buena Vista in Humacow, it was terrific. You arrive at a charming ranch in the coastal resort, where you are greeted by the friendly staff and sign a waiver. After that they divide you into experienced riders and beginners, that's when you mount your horse. It is hilarious watching everyone get on their horse (TAKE PICTURES!!!). Then you leave and you walk across beautiful puerto rican terrain, all the way to the beach. The experience of riding horses on the beach and seeing these beautiful post card locations is breath taking. I highly recommend this ride, the only down side is that it ends .After riding I suggest you walk around the city of Old San Juan, you will not regret it.