Ace Merrill has previously appeared on the big screen, played by Kiefer Sutherland in "Stand by Me," the film adaptation of the novella "The Body "
Easter Egg - The Number 19 The cabin Annie and Joy Wilkes move into is #19. 19 is a mystical number that appears regularly throughout the works of Stephen King, particularly the Dark Tower series.
Tim Robins plays Reginald 'Pop' Merrill. 'Pop' is a character in the book 'The Sun Dog' who is killed by a cursed Polaroid camera. In episode 1 of 'Castle Rock' Tim Robins' first scene shows him taking a picture using a Polaroid.
Ace Merrill is a character from "The Body", another short story by Stephen King.
The Kelvin gas station is a nod to JJ Abrams. The name Kelvin appears in all his movies including a gas station in "10 Cloverfield Lane".