i believe the green light he is talking about is from tommyknockers. i would love to hear back from you letting me know what you think. iv just finished this book and as soon as i turned the last page i got on here to see if it was listed but didnt see anything. hope it helps

tick tock man he has the same name as the character in the stand "the tick tock man" who dealt with explosives

SPOILER Pere Callahan describes wanting to use the door/black 13 to travel to 11/22/63 to prevent Kennedy from being assasinated. This portion describes a portion of the plot of the novel 11/22/63. Not a true hidden reference, but a cool insight into King's thought process, and perhaps this was the seed for 11/22/63.