I have played Congressional... in fact, I grew up less than 20 minutes from it in Montgomery County. I played it when I was executive banquet chef at the officer's club at the Bethesda Naval Hospital, nearly a million years ago (quarter of a century, actually). We had done a retirement dinner for a 3 Star at the Club (and 1100 of his closest friends... gods, what madness... largest group I ever served for one meal). As thanks, he invited the Executive Chef, myself, and our Manager to play a round with him (he was a member). Amazing place to play golf, it's my favorite of the Open sites.
Of course, we didn't play under Open conditions. If this courses sets up with Open conditions, rule #1: Stay out of the ball-eating rough. It was bad enough when I played it, especially since I spent a great deal of time there (I shot 92, the general won with a generous 83 by one over Chef... beer had a lot to do with the scores as I was an 80 average at the time, and the chef shot in the 70s). Great time was had by all, though.
I can't wait to play it here.