We will be going to Sunset Beach Resort & Spa. It isn't far from the dock, but we will take a taxi. It is 40.00 pp/ children 20.00. Includes food, open bar, water toys, ect. A really nice place! You don't book through the cruise line...just show up. We have friends that have been there numerous times and absolutely love Sunset Beach.
May I recommend a couple of reputable tour companys? They come highly recommended.
A-Z Jamaican Planners or Marva Shaw (knowjamaica.com) They do private tours, but will customize whatever you want to do.
Hope this helps! Enjoy your cruise!