We drive and can make it in about 8 hours, but we have gotten excited and left the day before and driven after DH got off work, we normally can make it to Valdosta or Lake City before we have to stop.
A cooler is a must, this way you can save money for important Mickey things. We would take the larger one, but I also would take a small collapsible one for when we would head to the pool. Again another way to save money at the pool, just remember no glass. Food bag with snacks, don't forget the wet ones for easy clean up.
Bring their games and electronics', possible a new game. ipad for movies don't forget the head phones. Check out the dollar store for Mickey items, I always stock them up, but like a previous poster suggested give them out over a period of time. Books, Coloring books, stickers, You can have them make envelope's for Mousekeeping's tips. Or decorate a poster for the window.
I agree with the one night bag Just PJ's and change of clothes for the next day.
When DD's were little, stopping somewhere to eat so that they can play was always a must so that they can burn off some energy and excitement. We like to stop at Chick Filet they have a play area but not really a huge one so it was easy to get them out and on the road again. Also another trick to burn off energy was when stopping at a rest area for a break we would let them race each other, but out of the way of other people. or we would walk the length of the sidewalks with them, this was great everyone got to stretch their legs a bit.
Have a magical time
