I'd fly. My brother drove from York Beach, ME once and it took a full 24 hours. I can't imagine looking at 3 long days down, and worse, 3 long driving days home when you are exhausted from Disney and sad about leaving!
Do you have your airfare yet? If it's on SW and prices drop (they have a sale), you can get a fare refund (as travel credits) or if you booked with Rapid Rewards you can get your points back. Also, if you have Early Bird boarding and your flight cancels, you will be in C boarding on whatever flight you are rebooked on, but they'll refund the EB. I know that doesn't help with wanting to sit with your daughter, though. If you can fly on Tuesdays and Wednesdays the fare is somewhat cheaper, and SW has been advertising a "Tuesday/Wednesday" fare sale for a while now.
Also, what hotel are you staying at when you get to FL? Mears Connect and Sunshine Flyer are $32 round trip between MCO and Disney area hotels. They go to more hotels than just those on-property.
Not sure if this is where I read it, but YES you should leave your Disney hotel about 3 hours before flight time. Having 2 hours at the airport can be cutting it close; the lines to check bags and get through security can be crazy, even at the crack of dawn. People might not choose that flight time, but with cancellations and rebooking, most flights are full these days.