I just found some Disney character Pez dispensers today at Dollar Tree. I bought Pooh and Daisy Duck, but they also had Donald, Mickey, Minnie, Tigger, Eeyore...can't remember if there were others. You can find Disney stickers just about anywhere. And how about including some Disney Dollars?
I'm planning to make several goodie bags for our long drive. I'm planning to give the kids one every 2-3 hours. They'll include a variety of treats and snacks, small toys, arts/crafts stuff, etc., as well as new autograph books and disposable cameras. I may even stick in a new DVD or music CD. Everything won't be "Disney", but I'll try to spread out the Disney stuff to keep the excitement going.
Among the toys will be a couple of things they can play with at rest areas for a few minutes to expend some energy (balls, etc). I'm also planning to give my DD7 a small latch hook kit and/or some other craft kit (she loves crafting).