For anyone who hasn't read it, check out "The Dark Side of the Game" by Tim Green.
Some of it might be a little dated now, but he gives a revealing behind the scenes look at the NFL. He touches on the subject of alcohol. Not sure if they still allow this but I remember him talking about guys pounding beers on the plane ride home after games.
The Dark Side of the Game: My Life in the NFL: Tim Green: 9780446605205: Amazon.com: Books