The GWL is by the NASCAR track and outlet mall. I know there is a T-Rex Cafe (just like DTD). The Kansas City T-bones baseball team plays there as well. Probably too early for a game but lots of fun and cheap! There is a huge Cabela's by GWL as well.
It's not a far drive downtown where more attractions are. Crown Center has a
Legoland Discovery Center, Aquarium, and Kaleidoscope kids creativity center/Hallmark Cards visitor center. There is a cool restaurant there called Fritz's where they use model trains to deliver your food.
Just north of Crown Center is Science City at Union Station which is a science museum for kids.
Just north of downtown is the Steamboat Arabia museum which is really cool. A family discovered a steam boat that had sunk and was buried by silt/dirt in a field near the Missouri River. They dug it up and have preserved almost all of the cargo. A very cool look at 1800's history.
The zoo is just south in Swope Park. There are better zoos but they are really working on improving it and just got a new polar bear.
I highly recommend that you try some good BBQ while you are in town. My absolute favorite in town in Oklahoma Joe's. Go to the original location in an old gas station on 47th St in KCK.
Hope this helps!
Jill in CO