Most people leave the Eating Rehoboth walking tour with a full belly. That’s because the 2½-hour trek through downtown Rehoboth Beach pauses at five eateries for samples. Ann Vaughan, however, took home an idea.  “Oh, my God, this would be so great in Kennett Square,” she told herself. That was in 2013. By 2014, Taste Kennett Food Tours was operating …