Chusei Yumegahara is a reconstructed medieval village in the Bisei area, laid out with old-style houses, farm buildings, and samurai residences. It is deliberately theatrical, but in a useful way: you get a physical sense of how a small settlement might have looked before modern Ibara arrived.
The site has hands-on activities and seasonal events, and it has also been used as a film set. Pair it with the observatory if you are spending a slow afternoon and evening in Bisei.