Last year we drove down from Baltimore.
On this site I found the website for I95 that lists every exit and what is there. It shows VA, NC, SC, GA, and FL. I believe it lists every hotel, eating place, gas stations, and even tells you where the cheapest prices for gas are. I printed this and some other helpful things that I found on these boards and made a book. Driving down we stopped at the welcome stations for every state and stopped in SC both going & coming. We'd look at the book and decided which exit we wanted. Also the website gives you estimates on the total travel time in each state.
As far as the kids went. We packed a cooler with soda, fruit punch, iced tea, and snacks. We brought our portable dvd player with 2 screens and movies--they might have watched 2 movies going down and none coming home. I also went to the dollar store and bought Disney related and travel related things for them --they played with them all the way down and back. Also had taken away their portable video game players and gave them back for the trip.
Another thing we did was to pack up the van the night before, and then (tried) to leave the house around 4 a.m.-- ended up being 5:30, but the kids slept for quite a while. I don't like driving at night, so my plan was to be able to travel as much as possible before traffic and the kids woke up. You figure if you leave at 4 a.m. and the kids go back to sleep until 7, 8 or even 9 thats 3-5 hours worth of traveling accomplished in peace & quiet!
Good luck. We enjoyed the time together and are planning on driving again this summer.