We did this in August 2004. It was about a 45 minute ferry ride to Rum Point. Great beach and had plenty of shaded areas. There are scheduled runs to Stingray City. We had about 45 minutes on the beach before we headed over to the stingrays. It was a short boat ride. We spent 20 or so minutes in the water with the stingrays. We all enjoyed it (excpet for my 12 year old who watched from the boat, but my 5 year old had no problem) and we all found it to be plenty of time. We then headed back to Rum Point to enjoy the rest of our stay. Our actual time at Rum Point wasn't very long though because of the ferry ride to and from Rum Point. But we all found it to be an excellent beach day and excursion. Grand Cayman is beautiful. Good luck with your decision.