ANTIQUES ROADSHOW arrives in Hartford, Connecticut, then ventures to Mystic Seaport for a glimpse of America's maritime heritage expressed in the Seaport's collection of rare paintings. Appraisal highlights include a 1963 poster for a Joan Baez/Bob Dylan concert at New Haven Arena, brought by the artist's daughter; a pair of 18th-century silk shoes purportedly worn by one of George Washington's dance partners; and a collection of 200-year-old Wedgwood pottery buttons found in an attic and valued at $1,500 to $2,000 for the set.