Jack goes to AA, but when Stephen King wrote the novel he didn't know about it so Jack didn't go in the book.
When Jack (Steven Weber) is looking through the paperwork in the basement, he finds an invitation to a masked ball. On the invitation it says "Dance to the Sounds of the Gage Creed Orchestra". Gage Creed is the youngest member of the Creed family, who was killed by a truck in Pet Semetary
When Jack is frustrated about his Alcoholics Anonymous program and begins to rant to himself about it, the blue book Steven Weber is actually holding is a Narcotics Anonymous book.