Hello and =welcome to Cruise @ddicts. =sailor
You and your family are going to have an awesome time on Mariner of the Seas. Your daughters will really enjoy "Fuel" the teen disco. One of the best kids areas I have seen on any ship :thumb
Your Western Caribbean itinerary is my favorite. Here are my picks...
Ocho Rios Jamaica: Dunns River Falls is the popular favorite but can be crowded. The rafting trip is really fun and not as crowded. Also stop by Jimmy Buffet's Margaritaville. They have a swimming pool with waterslide and a small private beach.
Labadee: Great Beach Day... we loved the wave runners.
Grand Cayman: If you miss Stingray City you will have missed the best thing there. Also go to the Tortuga Rum store right across the street from the tender dock and sample all the different flavors of rum cake, yummy!!
Cozumel: SNORKEL!! I recommend Eagle Ray Divers. Smaller, uncrowded boats and great snorkel guides. Do the three reef dive with lunch if you have time. Here's a link to their website.
http://eagleraydivers.com/
Another good website for Cozumel is
http://cozumelinsider.com/
One thing about Cozumel is that the tendering in takes a LONG TIME so plan to get off the ship as early as possible. Tendering back is not quite as bad.
=funsign on your cruise. I know you're going to have an awesome time!!