Hi Mudman,
We did the drive to WDW from RI two years ago with another family. Between us there were 10 people: 2 adults and three kids in each minivan. We too took a Tv/VCR and tapes to help while away the time. It was great. Instead of replying to "How long till we get there?" with a time estimate, we could say "at the end of this movie, we'll stop for lunch".
Our decision to drive was to make the drive part of the vacation, and do some sightseeing as well. So I don't know if our trip will help you or not.
We decided first that everyone would be more cranky as the trip went on, and we'd be better off to get the most hours in the first day. So we did our longest drive: 13 hours to get just over the state line into North Carolina. Traveling that route via 95 didn't offer anything worth stopping to see along the way. We stayed overnight at a discount motel right off the highway that first night.
The second day we stopped at South of the Border for lunch, ice cream and fireworks. Had to do it. The kids had been watching all the signs advertising it along the way. Glad we did, though.
Then we rewarded ourselves for getting so far without needing to strangle our children

by going to Savannah Georgia. That was our intention: to spend two nights there as part of our trip. Of course, it was lovely, and we all enjoyed it immensely. It's a very beautiful place. We toured a plantation, saw where they filmed Forrest Gump while walking along the historic blocks, and spent a very pleasant night on the riverfront there, enjoying the riverboats and the entertainment.
Then day four we left for WDW. That wasn't a very long drive. In fact the only delay we had was when we actually got into FL. The traffic was pretty bad that day.
On the way back, we drove up the coast. Again this was our intention: to see the sights and not to make good time. We stopped overnight the first night in St. Simon's Island, GA. Quite pretty. It was a shame we couldn't spend more time there.
Then, continuing up the coast, we stopped at Ocean Isle Beach, NC. It's just over the SC/NC line. We stayed at a fabulous little place directly on the beach there. Again, it was so nice there that we vowed to get back again some day for a longer visit. No one wanted to leave!
On the way back we visited Kitty Hawk, NC (where the Wright Bros had their 1st flight) in Cape Hatteras. We had one more overnight stop in Virginia. We had intended to stop in NYC to do the tourist sights, but we all decided to just drive straight through to home instead.
In order to spend more time at the places we wanted to see along the way, we limited our stops. Of course, we needed to stop for lunch, and the mother of the other family had a very small bladder, so we did have several mandatory rest stops.

Had it been just our family, we'd have stopped far less.
It was a great trip for us. I hope you enjoy yours as well.