Okayama is exceptionally well-placed for day trips. Kurashiki, 15 minutes west by the San'yo Line, has a preserved canal district (Bikan Historical Quarter) of white-walled storehouses that is one of western Japan's most photogenic neighbourhoods, plus the Ohara Museum of Art — the first Western art museum in Japan, with works by El Greco, Monet, and Renoir.
Naoshima has become one of Japan's most visited art destinations: the small Seto Inland Sea island hosts the Benesse Art Site, with Tadao Ando-designed museums including the Chichu Art Museum (built entirely underground around permanent works by Monet, Turrell, and De Maria) and the Art House Project, which places art installations in converted village buildings. The round trip from Okayama requires about five hours minimum; an overnight stay is better. Take the JR Uno Line to Uno port, then the short ferry to Naoshima.