When the weather gets hot in Sonoma County, there's no better way to cool off than with a float down the Russian River. A number of small towns dot the banks of the popular river flowing from Mendocino County to Jenner, but the best known of them all is Guerneville. On a recent scorchingly hot Thursday, I made the hour-and-a-half drive up to this river town of 4,500 from where I live in Oakland.