Seriously, make a schedule before you go, at east for the first few days? My wife is a pretty laid back mom, and I laughed when she told me that she was doing that a few weeks before our trip, but it made the trip. Seemed a little ridiculous to be planning which parks we would go to on which days and then the order in which we would go to rides and attractions and get speed passes, but that was a lifesaver.
Granted, our kids were a little younger than yours at the time, but remember to include some down time when you're not forcing hem to march around the parks. The key is to pace yourself as kids will be miserable after two days if you don't and meltdown potential becomes high. Hit all of the parks (not water parks), then return to your favorites or enjoy a water park later in the trip, wearing he kids out for the trip home.
With young kids, we pretty much ignored Epcot except for one night to see the parade and the fireworks and laser show. Bummer for me because I really enjoyed it as a teenager, but we planned to take the kids back when they were older. That didn't work out so well for me because trips to Orlando with older kids usually means Universal.
Make reservations for character lunches. Great times but I remember having to make those reservations well in advance. If you have a young daughter, do not skip the Disney princess breakfast on Cinderella's castle. One of the top moments in my life was watching my 5 year daughter dress up and meet all of the princesses. Most of them were really cute too.
For the most part, let your kids do what they enjoy. One of my daughters wanted to go on every ride. The other became obsessed with getting every character's autograph. We "fought" over which parent went with which child throughout the day. I usually lost (it wasn't really much of a fight) and took autograph duty. It was boring as hell at times and not what I wanted to be doing, but awesome memories just spending that time talking to her.
Also, you can stay on property (we stayed at the Caribbean and took the buses everywhere) and make note of the days when parks open early for property-dwellers (I assume that they still do this). Those times with smaller crowds were great to get the kids through the more popular attractions.
Then, next time you go back (and you likely will), take the less expensive, stay off property if you want, and enjoy a more freewheeling approach.
Lastly, if you can do it, I highly suggest combining a Disney cruise with a few days in the parks for a second trip. Easily one of the best vacations with kids you can take.
