I was there once and stayed with a friend at her time share condo so we could go do the "200 mile yard sale"... Crossville is a lovely, safe community. Someone who worked at the condo told us there was virtually no crime. I went out jogging in the mornings and saw lots of people walking dogs. There was a really nice fitness center and pool that we were allowed to use. I really didn't venture out much farther than that, but it's a beautiful place to walk, run or ride bikes. How about just spending time together as a family? Cooking... board games... reading.
I'm sure a google search or the local Chamber of Commerce could give you a run down of things to do in the area.