I agree with Jokir44. If she and the grandchildren expect to be entertained 24/7 you would not be doing them any favors. They would always expect more, more. When I re-married, my children were already adults on their own. My new youngest stepson was in his teens. The first time he cruised through the kitchen and living room to tell me "I'm bored." I told him not to try to make that my problem, it was of his own making. He seemed shocked. His father said he had always been that way.
Crossville is where we always knew we were not too far from home and family when we made trips back home to the "Delta" area. If you decide to make side trips into Memphis, there is also the Pink Palace museum. I think there is also a river museum. I recall that Crossville was a fresh, clean looking place.