Small, wrapped gifts to open every two or three hours. These were like dollar store material or cereal or fruit snacks, or the like. Kids respond very well to anticipation and excitement of a mystery gift. Additionally, the every couple of hours will help to break up the time in the car and make the trip seem shorter.

We also had a Dora the Explorer magnetic dress-up character pack and sticker books which were a hit.

Good luck, have fun!