I have to agree with Jim... For husband and I ship is the "excursion" for us. We are planning a cruise on Freedom in December 2012 (1st sun of Dec.) To be quiet honest I can NOT remember where we are going.. Look at cruise ticker..we are going there again(if it shows). We did a 4 night cruise through Disney. It was great but for your 1st cruise I would recommend min. Of a week. Pretty much all ships are pretty big and 4 days may not be long enough to do everything that is offered on ship (activities for kids and adults, and places to eat). We have only done Freedom through RCCL so I am no help when it comes to other ships.
What we do before every cruise(next year will be our 3rd) is we do a park before hand..RCCL works with Universal Studios. All transportation will be taken care of. And for us our RCCL reservation # was our reservation # for universal. just thought I would throw that out there for the kids ( and for those adults who are still kids, like us).