Ahead of our first cruise this October, I was actually researching just this and came across the following article which confirms much of what's been discussed here. YMMV of course:
http://www.disneycruisemomblog.com/guide-to-disembarking-in-port-canaveral/
Our flight home is at 3pm; understanding the airport will likely be a zoo by that time, I'm hoping do early breakfast in main dining or Cabanas when we open, get off the ship ASAP, then rent a car and make our way slowly to MCO, eat a slightly early lunch somewhere outside the airport at our own pace, and report to the airport by around 1pm (assuming that's enough time) for long trip home. Anyone ever done this?
Mark