A lot of freeway driving from Memphis to Nashville. then on to Chattanooga and finally Knoxville, but the countryside became more beautiful with every mile. An overnight in Nashville to see an old friend allowed a visit to see The Grand Ole Opry, the home of country music. The relatively modern building between the Opryland Hotel and a huge modern shopping mall wasn't what we'd expected, despite being (no doubt) much more functional than its Grand Ole predecessor.
On to Chattanooga the next day, we succumbed to the many, many roadside signs exhorting us to "See Rock City" and "See Ruby Falls" and took a diversion to the latter! We didn't go in (the 400 ft falls are in an underground cavern) but the twisty road up to it alone was worth the drive. Chattanooga no longer has a train station, alas, but we did find the Tennessee Valley Railroad Museum on the outskirts of town to count as a "Choo-Choo" sighting.