Day trip to Sawara
Sawara is an historic city located on the Ono River in Chiba Prefecture. From the center of Tokyo it's about 99 kilometers and on a clear traffic day, which is what we lucked out with on the Sunday we drove out there in May, you can make it to Sawara in about an hour. You can also get there by train on the JR Line from Tokyo Station (limited express, Tokyo-Sawara, 1 hour 30 mins.) or on the Keisei Line from Ueno. If you're transiting through Narita airport and have a few hours to kill you can get out there in about 25 minutes.
Check out the website in English at: http://www.city.sawara.chiba.jp/english/index.html for more detailed instructions on getting there & for some interesting photos and historical data about the city.
We drove out & parked at a pay-parking lot that is just a few meters from the canal and across the street from Fukushin (see the map of Sawara on the site above & click on the numbers). The attendant gave us a map (Japanese only) & told us about a coffee shop to try (near the Mitsubishi Kan) and about the water that cascades from under the bridge over the canal every 30 minutes (nothing spectacular, but picturesque). You can also park at the Ino Tadataka Memorial Museum (more about him on the site above also).
We didn't take the boat ride up the canal. Having been to Venice, Italy before we thought that this would be a bit disappointing - motorized skiffs "manned" by ladies in traditional farm wives' outfits (except for those jogging shoes!) didn't do much for us.
The actual historic area is small enough that you can walk around it in a couple of hours, but if you take in the museum you'll need to add that time in also. You can pop in & out of any shops that are open and in the shop on the corner, which sells a large variety of craft items, you can go up into the 2nd floor shop which is converted from the original warehouse. They have a very lovely little garden between the entrance to the back of the shop & the entrance to the upstairs warehouse shop.