I respectfully disagree with Baloo that there isn't much for a 5 yr old. We went with our DD8 and DD6 planning to spend 2 hours or so at DQ before conference check in, for DH who is a video game fanatic. Well, 4 1/2 hours later, I had to drag them all out reluctantly (yes, myself included) so he wouldn't miss registration and we still hadn't done half of what my girls wanted to do. We could easily spend an entire day there! Other than the typical video games, they have the create zone which both my girls loved. There are the virtual cruise and pirates which all ages can enjoy.
As far as a water park goes, you know your family, but my girls are just as happy with the hotel pool, so that's money that's foolish for us to spend. Also, how tall is your daughter? The slides do have height requirements (although I can't find my unoffical guide to see what those are. I'm sure a search on here would tell you).
No matter what you decide to do, you will have fun. Have a great trip!
