I've taken several long distance drives with my children (both boys, now 9 and 11). We consider ourselves somewhat professionals. We've never traveled with a tv/vcr.
1. I would start out very early (3:00am or even earlier if you can, pack the day before so you only need to put the sleepy heads in the car) This way you can get in some serious driving time before everyone wakes up.
2. We stop once aprox. every hour to hour and a half (that everyone's awake) for a 5 min. stop. Everyone must get out of the car and stretch (I make the boys run around the rest stop), go to the bathroom, and snack (if necessary). Although this takes 5 min. out of every hour or so, it keeps sanity up, and gives everyone a break, and no one needs to whine about going to the bathroom. We don't allow the kids to eat or drink in the car (we learned this lesson the hard (sticky) way), we bring snacks for them to have during the breaks. We NEVER stop if the kids are sleeping. We usually drive a couple of hours straight before a meal break.
3. If we're taking the kids out of school, all homework has to be done before they can play with any toys.
4. All toys, games and diversions are kept by the adult passenger in the front seat in a bag. No one gets a new toy until the old one is handed to us. This keeps the back seat from becoming a sea of toys, and prevents lost toys. We made the mistake of allowing the kids to have the bag this past trip - they destroyed the backseat, lost several toys, and were bored in about 30 minutes. Never again.
5. We try and realize when we are tired and need to stop for the night. We were driving back from Alabama and thought we'd drive through (to Philly). We became exausted in Maryland, about 6 hours from home. I realized I was becoming a danger on the road and got a hotel for the night (although I hated to admit defeat, I'd rather make it home alive).
6. If you decide to plan to divide the trip, we sometimes plan an on the road diversion (a cavern, or state park, sometimes we just stop for something that was advertised on a billboard). This makes the traveling part of the trip.
7. I buy a map for each child and let them follow along (this way our map never gets torn and lost in the backseat). We have the kids compare routes, tell us about the states we're in and find rest stops. We have contests on who can find the best/worst town names, and how long before we get to certain landmarks.
I hope you can use some of this. Have a great trip!