A Glimpse of Old Japan: Tokyo Edo Architectural Museum
There are many more buildings and exhibits to see (about 20 buildings total). One weekend a month, they have traditional crafts, and there are other special events throughout the month. The Tatemonoen (Edo-Tokyo Open Air Architectural Museum) English-language website isn't terribly informative other than the basics - details on admission fees, access, and hours, but for those just looking to visit it's enough.
Overall, I enjoyed the museum. It's not as good as Meiji Mura near Nagoya, but it is easily accessible from Tokyo. Then again, Meiji Mura is probably the best in Japan - the Historic Village of Hokkaido has as many buildings but Meiji Mura has really beautiful historic architecture.
You can visit Tuesday through Sunday from 9:30-5:30 (4:30 October through March). Admission is 400 yen. Access to the museum is through Hana-Koganei or Musashi-Koganei Stations, and then a bus; a long walk (25-30 minutes) from the train station is possible from Hana-Koganei, Musashi-Koganei or Higashi-Koganei Stations.