We take long drives all the time, at least two 10+ hour drives per year & several 2-6 hour drives. One of the things we do for long drives is leave at night (between 4 & 6 pm, usually around 4). We get a couple of easy, peaceful hours on the road, stop and get out (very important to stop a lot) and have dinner. There is another hour or two of peaceful driving before the kids are out for the night (bring pillows & blankets). It is here we try to get in as many hours as possible. DH usually goes down with the kids and I drive until I'm tired (about 11 pm or midnight) and he drives while I sleep. We switch as soon as one gets tired until the kiddos get up in the morning. If we're both too tired to drive, then we just go ahead & stop for the night & sleep in a bed. We then stop (if still driving which is the norm), get out, & eat breakfast. Then drive as normal for a long trip.
I can not stress enough with little kids how important it is to stop often. Let them get out, run around. I wish I had movies of DH & the boys running around rest stops doing calestenics; he makes sure all the kinks are worked out. Stop for every meal & GET OUT! Look for fast food or sit down restruants that have a play area--kids can always eat in the car & play while you eat if you want to save time. It might make the drive an hour or two longer, but a million times more pleasant so it actually seems shorter.
The things we have to keep the kids occupied between stops are a portable dvd player (it is only the bag that hangs--you can take the dvd out and use it anywhere & don't forget to check into your library for free rentals), a magna doodle (great for even the 14 month), lots of kid music, crayons/markers & coloring books (the color wonder stuff is great!), books on tape, some new toys (think dollar store), some favorite toys, plenty of snacks, and picture books. That's all I can think of for now.
We don't have the video now player. Our oldest is only 4 & right now I just don't think it is worth it. Maybe when he is 6; I know by then they'll be a lot nicer so I don't want to invest before I think it is worth while.