I recommend the link above, if you are constantly planning/dreaming a disney trip in your head, as I am, but more importantly for some practical tips that apply to any family travel.
When I took 4-under-3 to disney, and I knew that I would care how they looked in pictures, I put each outfit into a gallon ziplock. This way, they could grab a bag from their tote bag and bring it to mom, dad, or grandparent and be dressed in a flash, no digging through the bag for the matching shirt. This extra, OCD step was a big help.
These days, we often use packing lists, which allow the older children to do a decent job of packing for themselves. Usually, I write a check list on the white board and put their bags in the kitchen, and they have to come past me as they put things in so that I can keep an eye on it.
The one big tip I will take away from Elizabeth’s article is a “just in case” (motion sickness) bag for the car. We spend 3 hours in the car on Friday and Sunday nights, and while I am very lucky to have kids who are not usually car sick, we have had a random stomach flu hit us in the car — yuck! A kit like the one she describes would have come in handy many times already, and I am going to set one up to keep in our car all the time.
I do still need a better plan for the stuff that the kids use while in the car, it winds up all over the floor of the car and stepped on and ruined by muddy boots. I was thinking of putting in those organizers on the seat in front of you with pockets to hold some things? Any suggestions would be welcome.