OK, I'll try to give you some advise, but I'm no expert.
#1: Don't try to do the parks after driving all night. You'll wipe yourselves out the first day and be spent for the entire trip. Lay by the pool or take some leasure time to walk around the AS complex and get familiar with the layout. It's a big place! And go to bed at a reasonable hour.
#2: With the age of your kids, I would start with the Magic Kingdom. This is the park that they will probably like the best and it will keep them interested. Allow at least (30) minutes from the AS Music to MK on the bus (includes bus stop wait, etc.). Try and get to Main Street before park opening and go right to Town Hall for priority seating at Crystal Palace for the Character lunch. This will keep you from spending alot of time on lines for character pictures/autographs. Try and do any of the big rides you can do first (Splash Mtn., Space Mtn., etc.). BUT, don't run from one side of the park to the other to do rides. Use the map and work your way from one end of the park to the other. And definitely use the FASTPASS if the lines get long. It does not cost anything and can save you a bunch of time. The guide map will tell you which rides have FASTPASS. If you want to see a parade, be on the curb at least (30) minutes ahead of time and you and hubby take turns going to the shops, etc. with the kids.
#3: Take a break each day around 2 and go back to the hotel for naps/pool/whatever. Return to the parks for the evening. Make sure you check the operating hours when you arrive due to the cutbacks. Hopefully, at Christmas, things will be back to normal.
#4: Do NOT try and see everything in one 6-day trip. It is not possible. Sit down with the family before hand and go over the info on the WDW website. (Or try
http://www.wdwig.com/. I found this to be a real informative site). You might consider skipping a park this time and waiting for a future trip (my personal preference is to skip AK the first time).
#5: Take lots of pictures! If you have a digital, buy extra memory cards. If you have a conventional camera, buy the film in advance. You'll be amazed how quickly the trip will go by and the pictures will make the memories last a long time.
#6: ENJOY!! Don't let anything bother you. The secret of WDW is that you can completely forget about the outside world. Leave the cell phone/pager off and just have a blast. The real world will be there when you get back.
Good Luck! And have fun!!