While Nashville has a public transportation system, it may not be the most convenient option for a family with kids. Renting a car would be the best choice to get around and explore the city's attractions. Expect to pay around $30-60 per day for a rental car, depending on the size and type of vehicle. Traffic can be heavy during peak hours, so plan accordingly and allow extra travel time.
If you have more time, consider adding a visit to the Belle Meade Plantation or taking a riverboat cruise along the Cumberland River. If you have less time, skip the adventure Science Center and spend more time at the Country Music Hall of Fame and Museum or the Nashville Zoo. Be sure to book tickets for the Grand Ole Opry in advance, as shows often sell out quickly.