There are all kinds of cross book connections, especially in the Dark Tower books. So many characters from short stories appear in the books. The Black House is all about beam breakers (Ted Brautigan) even though it is a sequel to The Talisman which is a terrific fantasy-ish book. Flagg is in Eyes of The Dragon (also amazing). The baddie in Insomnia is The Crimson King.
In short, you will find yourself reading several King books and unexpected connections between novels will arise. I think Nate is going to be stunned at how many characters appear in more than one story.
One should forgive one's enemies, but not before they are hanged. -- Henrich Heine