A couple of other things I found interesting:
In a downtown waterfront park, there is a scale model of the Mississippi River. Minnesota to Louisana in a couple hundred yards! Quite an interesting walk along the length of it.
Also, for airplane nuts, the B-17 Memphis Belle is available in a nearby park.

You will love the drive down the valley from Memphis to the casinos. If you listen close you can almost hear the echos of the field hands of the 1800's.