We visited Andrew Jackson's home outside of Nashville. It was really interesting but also rather similar to Mount Vernon.
The audio tours were really nice. They had the traditional adult historical one, a kids option and a third that told the story from the perspective of Jackson's wife who died between the time he was elected president and took office.
The best part about the garden was the sprinklers... it was so hot that walking through the cool water was really nice.
This building was the "original" Hermitage. They lived here while building the big house.