We drove last Christmas trip (I went alone by plane in Jan) and we'll be driving again this August. We've done other driving trips/vacations before but this is the longest I think- closely followed by driving to Mi/Wi area to visit family.... in ice/snow no less. LOL I much prefer driving to Florida!
I can't really give you any suggestions that haven't already been mentioned- all great advice! You might find that you enjoy driving better anyway. I know I do... I have 3 young children though and I can't even IMAGINE what it would be like to have them all on a plane- even though my 5yr old is DYING to go by plane.... keeps asking if we can.
We drive (even though I hate the time lost to do so- it's about a 22hr drive) because it's too expensive for 5 of us flying and I'd rather spend that money elsewhere. But I do like the fact that we have the vehicle there- even though we're staying onsite this time. I do NOT like being trapped there unable to go anywhere except where the buses take you and waiting on the buses/etc. We'll probably use WDW transportation sometimes- but sometimes probably not. Plus then we can go to the store/etc. while there. We drove last time (staying offsite) but on my solo trip I got a taste of what it was like to be without a vehicle of my own while there and I didn't like it one bit. It would be even worse with having the entire family I'm sure. We could rent a car- but we'd need a minivan and it would be expensive. The cost of the flight plus the rental is just ridiculous compared to 2.5 tanks of gas!
Also I wonder how I'd bring along carseats that wouldn't fit the airplane seats! Britax carseats aren't the size needed for airplane seats- so that's something to consider and deal with taking in/out of the plane (WHILE also tending to 3 children) and deal with getting in the rental/etc. Just a pain to me. LOL
Also I like not having to worry about how much we can bring with us and how much we can take home- like you have to worry about that when flying. I can get a lot in our minivan removing the back seats. LOL We even took almost all their Christmas gifts last year (minus the big things like bikes). I didn't like having to worry about how I'd fit everything in my certain amount of suitcases on my solo trip for the flight back.
We have to make a lot of stops- or maybe we'd get there even faster- but that comes with the territory with young children... especially if they've just barely potty trained or are in diapers. LOL
We do switch off and drive at night but I don't suggest that for MOST people. It only works for us because I'm the type of person that is up all night anyway- so for me that is my most "awake" time. I sleep while he drives during the day and he's not tired because he slept all night and we make a lot of frequent stops. I drive during the night when I'm most awake. Not everyone is like that though and might have trouble staying awake- that would be very very bad. Don't chance that! If I wasn't a nightowl/insomniac- I would stay overnight somewhere. We might do that this trip depending on how I'm sleeping at that time. I go in phases lately where sometimes I sleep at night, sometimes I sleep during the early day- depending on my husband's rotating shifts schedule. LOL
Good luck and have fun driving!