We walked into the park, entrance cost us $2.50 apiece. We took a very pleasant walk down one of the trails then walked the beach. One major warning - lots and lots of rocks on the beach. You do NOT want to walk barefoot on this beach! The water was great.
We rented snorkeling gear from the kiosk ($13 per person for mask, snorkel and fins). There are 3 rock groups that you can snorkel around. The water goes to about 6-8 feet deep once you get past the first 20 feet or so. In spite of a really windy day we saw lots of cool fish and got some good pictures. Looking forward to a repeat visit.
Another warning - you can rent chairs and umbrellas...very expensive and they can't be moved around. I would avoid this.
Highly recommend a visit to this picturesque park.