My visit to the Dickinson mansion, which is called "the Homestead," was the highlight of a recent return to Amherst College, the small liberal arts institution from which I graduated in 1979. The college owns the house and a neighboring one, "The Evergreens," a stylish Italianate mansion built for the poet's brother Austin. The two form the heart of the Emily Dickinson Museum, which drew 15,000 visitors last year, according to the museum's executive director, Jane Wald. I spent extended time in both houses because I'm writing an architecture guide to the college.