Vanderbilt Mansion in Hyde Park NY. I have been here a few times but this time we took a tour and walked most of the grounds. There are views of the Hudson river. The guest house is where you can buy tickets to go into the house with a guided tour. Also in the guest house there is a gift shop. From the guest house you can walk to the main house and to the gardens.
Inside you get to see some of the rooms and how they would have looked. When I went you could not go to the 3rd floor because it was hot. Before you leave there is a spot you can pull over called the over look, great view of the land and the river.