Kimitsu runs from the industrial shore of Tokyo Bay deep into the forested hills of the inner Boso peninsula, and the contrast is striking. On the coast, the Nippon Steel works stretches for kilometres, a tangle of furnaces, chimneys and cranes. Inland, within half an hour, you are among steep green hills, narrow valleys and reservoirs, with hardly a building in sight.
The scenic heart of the area is Kanōzan, a low mountain with an old temple at the top and a viewpoint over the Kujūkutani, the ninety-nine valleys. On autumn and winter mornings, mist often fills the valleys below, creating a sea of clouds with the ridges rising like islands. It is a famous sight, and photographers gather at dawn to capture it.
The Kameyama dam lake, further south, is a long, winding reservoir surrounded by forests, and in late November the autumn leaves turn the slopes red and gold. The roads around the lake are narrow and twisty, with little traffic and fine views.
For riders, the inner Boso offers a network of quiet roads with tight bends, steep climbs and tunnels. The tarmac is decent on the whole, though leaves, moss and fallen branches can make the roads slippery, especially in autumn and after rain. Watch out for deer and monkeys, which are common in the forests.
The Aqua-Line, the tunnel and bridge across Tokyo Bay from Kawasaki, lands in nearby Kisarazu, making the area easily accessible from Tokyo. Do your shopping on the coast. The hills are thinly populated, and the stations that do exist inland keep short hours, so leave the bay side with a full tank.