More from Andrew Bikichky's Tweets ...
Andrew tells us the cast will crack each other up especially when they are all together for a scene. One fact about Castle, is that they do not use fluorescent lights in the Interrogation room. According to Andrew the aerial shots of New York are usually what they call "stock shots".
@CastleArtdept put up all the strings in the room in ‘LinchPin.’ When Castle and Beckett were looking into the water, that scene was shot with a 50ft technocrane. It took 2 shoots for the car crash and Nathan and Stana were there.
Here are some photos Andrew has posted to Twitter: