Wedged along the borders of Connecticut and Massachusetts in northern Dutchess County, Millerton used to fly under the radar. In the past five years, in-town development from artists, designers, and makers has elevated the profile of its throwback Americana Main Street. Once dubbed “the Williamsburg of upstate,” Millerton has held on to its reputation as an undercover outpost of haute Brooklyn. But locals have grown weary of the hype, and the comparisons.