When we drive straight through to WDW it's about 17 hours of driving, plus some stops... but our longest straight through was 41 hours. (Chicago to Portland).
Here are my 4 top tips:
1. Drive as many hours as you SAFELY can during the night so the kids can sleep, and you reduce the number of meal breaks. Stopping for food really does take a lot of time, especially with kids. DH & I are both good nappers when it comes to long drives, and have no issues switching off. But we are careful to cut our losses if neither of us feel up to driving. Better to spend a night in a hotel than fall asleep driving.
2. Let the kids have any electronics they want. Our kids are pretty restricted when it comes to screen time, but not on long drives. If they want to watch 4 back-to-back movies that's fine with me because it means I just drove 7 hours without anyone asking "are we there yet".
3. Stop often to stretch (at least every 2-3 hours). Short stops are fine, but you will be amazed what 5 minutes of walking can do for your circulation. We love to play "silent tag" at rest stops in the middle of the night.
4. Be VERY careful about tipping seats back. A seat belt that is floating in mid-air over someone's sleeping body is not going to do any good, and could actually cause a lot of harm, in an accident. Better to bring a few extra pillows and keep those seats upright.
Have a great trip!!!