Driving cost us $700, round trip with hotels. You can go cheaper than $150 a night in a hotel, but I wouldn't recommend it. We hit a motel 6 last year, and the place was the most disgusting room I've ever been in. This year it was just the Hampton inn as they are consistently nice and clean. I wing it as far as booking a hotel. I don't want to force my self to stop if I can keep driving and also I don't want to force myself to keep driving another 50 miles if I'm tired.
The drive isn't bad as long as you can go all out the first day and have a short drive for the final stretch. We pack up the car the night before and then wake up at 3am, throw the kids in the car, hit Tim Hortons for a coffee and then off we go. I have a Microsoft Surface tablet that I have 24 hours of cartoons on a playlist. Looney tunes, old Disney shorts and various other shows all ordered so it's more like watching a channel and not watching one series over and over in case one kid doesn't like something. The tablet feeds the DVD system in the car so there's no discs to deal with and they can all have their headphones on.
Caffeine is the key to driving that far, but at the same time, you can only drive as far as your kid's bladders allow without making a pit stop. I have my phone with the Waze app running so I can see if there are any upcoming cops/traffic/slowdowns etc.. ahead and then act accordingly. We've hopped off of the freeway and then back on 5 miles later to avoid an hour of traffic.
We've now made the round trip drive twice and all worked out well. We get to WDW just after noon, check into the hotel and drive to downtown Disney for a late lunch and then hit the pool. I'm hoping to do it again next august.