I recommend booking your excursions before you leave....that way it's one less thing to worry about once on board!

With PALO, Spa reservations, and, Kids Club registration (if you have children)
You will have plenty to do....we always get together a few days before the 60 day mark for booking and pick out what we want....on the 60th day we call and it's done! There were people on our last cruise screaming at the excursion rep because the excursions they wanted were SOLD OUT! I think its a little much...after all, they get the same slip in their documents that says...you can book them 60 days ahead of time!
I'm not sure what sells our on the 3-4 day cruises....but on the Eastern....the dolphin encounter, the golden eagle catamaran, the 12-Metre Regatta and Rhino Rider. Those were a few that the lady told me about.....And when she checked......they were already sold out for our out eastern at the end of August....
The Western....I know the Stingray encounter is sold out very quickly!! IT'S THE BEST!!!!! I recommend it..We would do that again in a second!!
Hope this helps....Here is the Excursions Desk number...(877) 566-0968
Travis