West Palm Beach -- visiting, looking for recommendations

DH and I are headed to WPB on Monday to visit our son who recently moved there. Restaurants, things to do (I know there's lots)? Unique food that we can't get home in PA? Other advice? DH went to Disney when he was a teen but I've never been south of N Carolina. We're taking the Auto Train to Sanford (how long a drive to WPB?) and Amtrak home to Philly. Thanks!!