Carrie Classon’s, “Blue Yarn: A Memoir,” is available at Amazon, Barnes and Noble, and other fine stores. Learn more at CarrieClasson.com. My husband Peter and I are staying in San Miguel de Allende, Mexico, which is, according to a lot of folks, a tourist town. Sometimes, the person saying this means it is not a place they would want to spend time. This puzzles me. I’m not sure why a town known for meatpacking or manufacturing would be a better place to spend time than a town known for tourism. But I respect anyone’s right to spend time wherever they want, and Peter and I are happy in San Miguel, in large part because it is a tourist town. A lot of the tourists are from the United States. A surprising number are from Canada. “Is there anyone left up there in the winter?” I asked a Canadian visitor I met at the writers’ conference last week. There were more Canadians in the audience than folks from the U.S. and Mexico combined. I found this astonishing, considering that all of…