for a 2 year old i would NOT do disney, they are too scary at that age and boring in parts. I would stick with thomas, and elmo, Music Cd's might be another good idea, Raffi is our favorite, that way he can listen to short little songs and finger plays, i would let him listen at home so he gets familiar with them. Another idea is bringing a big pack of stickers. at that age they like to stick them all over themselves, you can say put the blue sticker on your nose etc.
He might be a little bit young, but we went on a big car trip and i wrapped a little gift, fruitsnacks, a hotwheels car, stickers, even some toys from home, etc and at each point in our trip, usually half way between meals, i would let him unwrap a gift,
guess that's alli've got, hope its a great trip.