So it's ironic that circumstances have conspired to take me there 31 times. Those are my credentials. Nashville is easy to deal with, especially the airport. The city is relatively small and well circled by highways, so getting around by rental car is easy.
Cars are relatively inexpensive and readily available right at the airport.
In fact, it's the second-easiest place to rent a car I've ever experienced. Buses are limited, there's no subway, and excursion based on cab fare would rapidly exceed the cost of the rental car. Grayline Buses can get you to your hotel. Most of the tourist shops, many of the restaurants, and much of the night life in Nashville are downtown, all within easy walking distance of several excellent hotels. The jewel of the bunch is The Renaissance.