Nice road, but I'm not as enthusiastic about it as Orson. It's very pretty, but also tends to have quite a bit of traffic on it when the weather is nice. Its main stop, Guerneville, is a fairly bohemian town along the Russian River, and is quite popular as summer resort town. All in all, more of a cruising, enjoy the scenery road than a playful, sporty road. It is a pleasant way to get from 101 to the coast and back.
Look instead for some nearby alternatives such as the Bohemian Hwy, Coleman Valley Rd, or turn off 116 to go to Cazadero where you can pick up either Fort Ross Road or King Ridge Road and have a real adventure, with little traffic, little police presence, and lots of fun on narrow, technical roads.
Pro tip: The great secret of riding the California coast from San Luis Obispo all the way to Leggett is that the coast mountains that separate highways 1 and 101 are criss-crossed with dozens of little roads that are often lightly trafficked, and are mostly big fun. Look for the ones that are not designated state highways so that you can escape the crowds.
Highway 116 takes you through magnificent groves of towering redwood trees. After the town of Guerneville, it follows the Russian River all the way to the town of Jenner on the coast and the equally glorious Highway 1.