On our first cruise, we were at WDW beforehand. We decided to go to one of the parks before we left for the ship. Didn't get to the ship until 2:30 or 3:00. We had lunch in Orlando before leaving there, and then had lunch on the ship again (didn't know there would be food waiting for us
).
We just needed to sign the kids up for the club and lab, that took a little while, didn't want to do the spa or Palo so didn't have that to worry about. Before we got settled down and able to find our way around the ship it was time for the safety drill, spent a little time at the sail away party, then having to get unpacked and dressed for dinner (eating again already are we?). Made for a very rushed, fairly stressful time - duh!!
Since then we have arrived early at the port and waited in line OFF of the ship. Spending time waiting in lines before boarding is much, much, much better than waiting in line ON board. Just like the parks, the earlier you can enter, the more stuff you can get done in a shorter period of time. You spend just a little time taking care of the things "you gotta do" once on board, then you can get to the serious business of partying and enjoying your vacation.
Having to fly to Florida, we will always be "in state" on the day before we sail. The stress of missing the ship because of flight delays are not worth it. Like "Denver" said, they can have blizzards that last for days so from areas like that I would plan accordingly (and leave town earlier
)