I took a tour with a friend so that she could see another part of Japan. We visited a temple where we were able to see traditional Japan, had a traditional Udon and grilled fish lunch, and then enjoyed the scenery. A must see and do for visitors and a great place to escape for Tokyo locals. As enigmatic mentioned, book in advance.
A beautiful place to go to get a breath of fresh air in Tokyo. It is very peaceful, you will forget that you live in a hectic city. Make sure to visit during 'coming-of-age-day' in Japan when all of the 20 year olds get dolled up in their traditional finery.