We're from San Francisco and got the surprise of our lives last year when we discovered Princess was going to fly us in on the same day. Most cruise ships leave around 4:30 to 5:30pm, making it difficult to fly West Coasters in on the same day. But the 7:45pm departure time of the Grand Princess makes all the difference in the world. They had booked us on a Delta "milk run" flight leaving at 6:00am, arriving in Ft Lauderdale at 6:00pm. No way were we going to spend our first day of vacation worrying our way across the skies!
Luckily, at that time, we saved nearly half by purchasing our own airfare over what Princess was charging. We did things right by flying in the day prior and booking a hotel.
My advice is to continue pricing airline tickets between now and your final payment date. If and when you can obtain comperable airfare on your own, then go for it. If not, then pay the deviation fee to either fly in a day early or on a red eye. We will never fly the same day to Florida from California. Good luck!