We are trying to go on the cheap...but some things I am planning to do (I have a 1 year old and a 3 year old, so the trip is centered around them) are:
the
Lego store (and let them play with the legos and check out the lego statues)
Play in the splashpad area
Catch a movie at the AMC fork and screen theaters (where you sit down and they bring food to you)
$3 train rides and carousel rides
And, I recently learned that there is a Groupon for the Characters in Flight tethered hot air balloon ride. It will save you a good amount for this very unique experience. If you can, read about the company...
The groupon is available here:
http://www.groupon.com/deals/aeroph...campaign=77ad64ef-edca-439a-875e-05d8ace81aa7