I've been there twice in 2 years. I actually was just there in July. With that being said, i can recommend that you explore Old San Juan. Make sure you eat at Cafe Puerto Rico. They have the best mofongo and yellow rice. For breakfast, make sure you check out Cafe Mallorca and enjoy their mallorcas with some ice cold lemonade. If you're into activities like ATVs, climbing etc, check out Campo Rico (Camp Hacienda). ATV rentals there are relatively cheap (don't let them sucker you into buying those expensive wack ass glasses and handkerchief). Also, if you like jet skis, check out Aquatica.