If you have to drive, I must admit that the DVD player was worth the $100 investment (included 2 screens) for at least giving a change of "scenery" now and then.
We also loosely followed our daily routine to break up the drive. Stopped for lunch, read some stories (in the car), then naptime as we drove. After naps, a video and snack - just like at home.
On the last 24 hour road trip we also made a map. My 3 year old didn't completely get it, but she was THRILLED when we finally pointed next to Grandma & Grandpa's house.
P.S. New to your community, but agree - kindness and chocolate. Yum!