I also agree that going down the day before is almost always a great idea. Case in point...
My wife and I were going on the Adventure out of San Juan last January and had booked a room at a nice resort the day before (which was a Saturday). Our flight was an hour late leaving Gulfport and by the time we got to Charlotte, our connecting flight had already left. The next flight we could get on was 8.5 hours later and we would have missed our cruise if we were to leave that day.