The Avon Ring can be circumnavigated in a week, but two weeks gives you a chance to get out and tour the towns and countryside. Most boating companies will buy groceries for you, so you can leave the docks with a full pantry. There are numerous opportunities to purchase fresh produce and other supplies along the way.
Anglo-Welsh Waterway Holidays (www.anglowelsh.co.uk) is the largest operator of canal boats in the U.K., with more than 170 boats and 10 centers throughout Britain. Book through the Bristol office, at 44-117/924-1200.
Boats can be rented mid-March through late October, for anywhere from one night to several weeks. The weekly cost depends on the season, but in high season—the end of July until the first of September—a boat that sleeps four costs just over $2,100 (off-season, it can go for half that amount).