This fantastic yet overlooked museum is a preserve for historic buildings rescued from around Tokyo during the city's decades-long construction jag. Among them are an Edo-era farmhouse, a modernist villa and a whole strip of early-20th-century shops, all of which you can enter. The museum is inside Koganei-kōen (Tokyo's second-largest park) in Musashi-Koganei (four stops past Kichijōji on the JR Chūō line).
From the north exit of Musashi-Koganei Station, take a bus from stop 2 or 3 for Koganei-kōen Nishi-guchi, from where it's a five-minute walk to the museum through the park. There are more detailed directions on the website.