I was fooled by the pictures thinking this was a ginormous castle, but sadly, it was not.
We came here with our citypass ticket to walk the grounds and was thoroughly unimpressed. I would save your money and just snap pictures for free from out front. Our ticket also came with the audio tour, but I didn't use it even though you have to walk downstairs to get it, and then go back downstairs to return it. What an inconvenience.
I would also skip the tunnels in the lower levels as it led you to nothing really spectacular. It had a moldy mildew smell down there, as well. The second floor had a few rooms with classic furniture and history.
I think I enjoyed the back gardens the most with the fountain. It was picturesque and nice to sit in the shade and enjoy some gelato. They were remodeling one of the towers so you don't get a perfect picture though.
I wouldn't come back or pay full price for admissions. Parking was $10 on a Friday all day, so we left our car there and went by public transit to explore the rest of downtown by foot since we paid for parking.