Oh so many places especially to see, there is the Grand Old Opry, the Parthenon, Bell Meade Mansion, of course downtown Nashville, Country Music Hall of Fame, Gaylord Hotel, Dollywood in East Tennessee for your son, there are great campgrounds in Nashville and East Tennessee.
I forgot, there is a Civil War battle ground in Murfreesboro about 20 miles south of Nashville and several more throughout the state. If you want more info just let me know.
If your staying in Nashville I would recommend the KOA, it has shuttle services to a lot of the places I mentioned
Fly Fishing Crazies
Sage and Winston