Have you seen Crayola's dry erase crayons? I think they'll be fun for a car activity book, don't you? I bought a 5-1/2x8-1/2 binder and filler pages.
Other pages included:
-a page with her full name and address so she can practice writing it.
-cupcake to decorate for her birthday, and the birthday date next to it
-a blank "paper doll" to dress
When she's done coloring on the plastic page protector, she can erase it and draw again another time! Her father is quite an artist too, so he can add more pictures any time. As her favorite characters change, they can always add new characters too.
Have fun, T!