As
@fredandkell mentioned there are many options. I’ll start more general and give the 10,000 foot view. Some of this can depend where you might be flying from/arrival times as well as personal perferences.
- Airport stay - if your flight arrives later on Saturday or you have a long travel day you could just get the Airport Hyatt or other nearby hotel. Crash that night, relax and prep on Sunday and depart fresh and ready for your cruise on Monday
- Beach day - if you want a beach day before the cruise you could just head over to the coast after arriving on Saturday. Most places have shuttles to the port. You can do the beach, space complex or have dinner and watch ships sail out before the cruise. (Bonus if you can make the Saturday afternoon sail away as the Fantasy departs that day)
- Disney day - stay on property or nearby and do a day at the parks or Disney Springs, (or dare I say it - Universal). Sure it would only be a day but why not squeeze in a few rides, characters, a dole whip, turkey leg or whatever your WDW favorite might be.
Once you pick from one of those three, it will be easier to plan and work out your logistics.