We have been driving for the 20 past years, sometimes 2x a year. We took our oldest for the first time he was 2, then DD came along, they are now 21 and 18.
Driving with young children ask for more planning, KEEP THEM BUSY!!!, DVD, I pod, game boy or wathever technology you have, keep snacks on hand. I used to go to the dollar store buy all kinds of little things, I made surprised bags and then gave them along the ride (2 or 3 each).
We tried different ways, stopping for the night, drving thrue, leaving at 4am, noon, midnigth... All of the options have good and down sides. I guess you will have to try a couple of them to see what goes better for your familly. We always fell that going staight thrue goes better for us.
When you leave you know that around the same time on the following day you will be in the Magic...

It is always between 23-25 hours,
Now, we sometimes go without the kids

and still keep it that way. The best part of going with the kids now is that they can drive!!!

Have a magical trip.
1990 to 1999 Off site
2000 to 2003 All star Sports
2004 to 2011 Pop Century
2012 The World was great again (Pop Century) without the kids for the 1st time
2013 March Disneymoon with the kids
2013 September 2th adult trip, kind of another Disneymoon
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