Most people who visit Calistoga -- a town in the Napa Valley -- come for the wine and the spa treatments; few come for the literary history. But they could: one of the most romantic honeymoon getaways ever written about happened one hundred and thirty five years ago. Instead of mud baths and geysers, picture an abandoned mining shack infested with snakes, poison oak, and rusty nails. Now picture a sickly writer and his new wife spending their first two months of married life living there. Sounds crazy, right? But that’s exactly what Robert Louis Stevenson — author of the...