Actor Tom Hanks' production company is filming a 10-part miniseries about Revolutionist John Adams. In Williamsburg, Richmond, and Europe.
Philadelphia and Boston will provide zero backdrop according to this story.
I'll bet that the producers judged Williamsburg a "truer" location than Boston because it offers a stronger undiluted "Colonial" impression than modern Boston or Philly. In other words, the false but rich visual has more chance of connecting with the viewer than the true: the rooms Adams wrote in or debated across are of less interest than something chosen or built for movie purposes.
You know, Adams himself holds little visual interest. Why not have Stonewall Jackson or Calamity Jane working the Constitutional Convention instead? That has "hit" written all over it.