Where to stay outside of San Jaun in Puerto Rico?

Question

I have a business trip to San Juan. I would like to take a few days and get outside of the city and stay at a beach. I am having trouble figuring out what to do. I don't like big resorts and all fancy. I want nice but not the Ritz, in other words. I like low key, casual and smaller place that is on the beach or close to beach with pool. Anyone have any good ideas? Thanks.