Sorry nobody has responded since your post. From what I have read, your safest bet is to do an organized excursion in Jamaica, either through the ship or through another vendor. For me personally, in October, I'm using Shoretrips, which most people on this board like.
2007 - Majesty of the Seas (Bahamas)
2009 - Enchantment of the Seas (Western Caribbean)
2010 - Freedom of the Seas (Western Caribbean)
2013 - Golden Princess (Alaska, roundtrip from Seattle)