The place isn't very large, and the interiors are mostly furnished as they were, giving it a strong historical feel. An hour is enough to see everything if there are few people. A unique feature is the front courtyard, a traditional Chinese courtyard house, contrasting with the Western-style building in the back, allowing you to see two different residential styles simultaneously.
However, during the National Day holiday, it was incredibly crowded. There were queues to enter any room, and the queue for the Grand Green Building was a two-hour wait. Due to time constraints, I didn't queue and only saw the exterior.