Getting to the downtown area of Nashville is about a 15 min cab drive away from the local airport and walking around is common in this area. There is the strip on which you can wander from bar to bar to experience the local ambiance. Some have said that it is a bit "run down", but I disagree. To me it has a true feel of a downtown energy with lots of character. Many of the places are family friendly with local bands as well as some established local legends. If it is an adult-only trip, Robert's Western World, has been described as a fun but typical Nashville "dive" with great music and the some of the cheapest drinks in town.
Check out the Country Music Hall of Fame, the Ryman's Auditorium where you can take in a show, and the Grand Ole Opry house. Make sure you preview what the upcoming talent is and secure your tickets in advance. Since Nashville has a high population of very talented college kids trying it make it big in the entertainment industry you might just get one of your only free concerts from a big name future talent!