I fill disney themed party bags, get them on clearance, with little goodies and snacks/candy. I pick up items on clearance throughout the year and start assembeling the bags about a week before we leave. I have included disney candy and fruit snacks, beeanies, pez dispencers, temporary tatoos, disney themed party favors ( I used the mickey parachutes a couple of years ago and the last two from the package will go in this years bags), disney books and stuckers etc. I just put them on top of the dresser when I get up and the kids find them when they wake up.
I also do a travel bag for each kid before we leave. I have puzzles, books, cross words, new music, maybe a travel game, and snacks or other essentials they might need on the drive (tissues, lip balm, lotion). I found great plastic notebook holders/binders/file folder combo a couple of years ago and I load it up with puzzles and games I print off.