We just drove from Baltimore to WDW in June. What I did with my 3 kids was pack them a "surprise" bag. It had juices, snacks, car games, little toys, mini fans, glow sticks, & all kinds of other fun stuff. We brought our portable DVD player & let them watch a couple movies on the way down. We didn't even bother to turn it on on the way home.
I didn't make any reservations because I didn't know where we'd stop. I wanted to leave our house at 4, but we didn't leave until 5:30-- anyway the point was for the kids to fall back asleep so we could get a several hours worth of driving under our belt before stopping for breakfast.
We drove down I95. I went to the I95 website & it listed all the states from VA thru to FL. It told me how many hours it would take to drive thru each state & some other little trivia. It also listed every exit for each state & what we could find there as far as food & lodging goes. Both times we stopped at SC to spend the night. I printed this information out & made a book. As we were ready to stop, we could just pull out the book & see what each exit offered. It even listed the places that sold the cheapest gas.
I was so proud of my kids on both drives, but they did have plenty to entertain themselves. Also at each stop I made them run around to get some exercise.
Good luck & have fun!