Try to catch or record SNY's Mets Weekly this week during one of its scheduled reairings: Monday at 1:00 PM; Tuesday at 6:30 PM; Thursday at 6:30 PM. The extraordinary New York baseball historian I wrote about  a couple of weeks ago, Peter Laskowich, is featured, giving a mini-tour of Manhattan baseball landmarks, specifically Madison Square Park and Coogan's Bluff. Next week (noon Saturday) the show follows Peter to Brooklyn for more of the heritage that led to the Mets.
(Don't know if he'll stop off at Washington Park, but Jason did recently, which you can read about here .)
Can't recommend Peter's baseball tours enough. Check his site here  for more information.