This is a great place to spend a free day in Puerto Rico! There are many interpretative trails in this park, and all are free and open to the public. Some lead to caves, others lead to beautiful views.
There are also many covered areas for picnics. The trails are mostly leveled off and easy hikes, although some can be a bit more challenging. Be sure to bring lots of water, as it can be humid. Also, bug spray will be your friend! If you plan to take a trail that leads to a cave, be sure to have a flashlight with you as well.
You can also camp within the park. It costs $4 per night for adults and $2 for children under 10 years old.
A popular hikes within the park is the 3.2 kilometer (2-mile) long interpretive trail loop. Be sure to make the detour to the observation tower along the route—the short side trail is strenuous but the views (and breeze!) are worth it.