Kawasaki

One of the best museums in Tokyo is the open air buildings museum at Kawasaki, (known as Nihon Minkaen) where they have brought traditional, Edo period, buildings from all over Japan, so if you are feeling very lazy, or even just totally out of your depth, you do not have to cover the whole country. Of course there are other similar museums elsewhere in Japan, although those mostly comprise buildings from the surrounding region rather than the whole country.