In the sweltering heat of Manhattan, even the prairie plantings on the High Line looked dusty and tired. I usually steer clear of the city in summer, but this year I arrived in the middle of August. It was the night of the supermoon and I went down to the river to try to catch a breeze. On Pier 45, couples were dancing the tango, twisting and dipping as the music drifted out across the water. The sky turned pink and right on cue the moon rose luminous behind the towers. The next morning, I caught the Amtrak Adirondack train from Penn station. Named after the mountain range it passes through, it runs up the Hudson and on to Montreal, calling at old industrial towns with names familiar from William Kennedy and Philip Roth novels: Albany, Poughkeepsie, Schenectady.