Kayak San Juan Puerto Rico

Which is better worth my while in Puerto Rico?
I will be vacationing in PR this coming July with my husband. We only have 5 days there, and our hotel is in Ocean Park. I am planning our itinerary, and so far, I am planning on going to Ocean Park beach, touring Old San Juan, visiting El Yunque Rain Forest, taking a kayaking tour of the Bioluminescent Bay in Las Croabas, and going to the art museums.
On the last day there, we are deciding between going to Camuy Caves/Space Observatory/Caguana Park or taking a day trip to Culebra Island. We are going to have a rental car. Also, are restaurants in Old San Juan open late? I was hoping we could get dinner there after either one of these trips. Both trips sound really fun, and we can’t decide. For those of you who have experience with these sights, please share your opinions! Thanks so much!
Since the only beach your going to is in the city I would suggest going to Culebra. Check out the ferry schedules and provide yourself with enough time to get there at least an hour before the first ferry. Culebra has the Caribbean’’s second best beach, Flamenco Bay. You can save a lot of time and take a flight there from Isla Grande Airport, it costs more but it’s a mega time saver which gives you more time on the beach.
Camuey Caverns is an amazing site, so if your not that into white sand blue green waters it’s a great alternative. As far as the restaurants being open late it depends what day of the week your doing this on.
http://www.islaculebra.com/puerto-rico/culebra-ferry-schedule.html