If it's the same itinerary I did for my very first cruise, then your ports of call are Nassau, CocoCay, and Key West?
It really depends on what you want to do. I too, would recommend Atlantis while you're in Nassau. It should only be about a $5-7 USD cab ride to it from the pier. Aside from that, it depends on what you want to do. I did parasailing and snorkeling in CocoCay, which is Royal Caribbean's private island, so like with Labadee, if you were there in the past, you should be the only ship there. That's also a good beach day if you just want to lie on the beach.
As far as Key West, that again depends on what you want to do. I'm a water type person, so I did a glass bottom boat tour, and parasailing a second time. Bear in mind, between CocoCay and Key West, you may have to go declare yourself to a customs official on the ship, as you are going from a non-US port to a US port. I'm not sure if it still works this way. This is what we had to do when I was on the Majesty of the Seas back in 2007.
I'm trying to decide what to do for my next cruise. I'm thinking maybe a 7 night Eastern Caribbean cruise late next year. I can't decide whether I want to stick with Royal Caribbean, or try Carnival for a change. Don't get me wrong, I've loved Royal Caribbean in the past, I just might want to try another cruise line to see how it compares to Royal Caribbean.
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)