I hadn't read King until about 2003, when I picked up a paperback of The Gunslinger at the local pharmacy while waiting for a script. I liked the book enough to continue on with the series, and I absolutely fell in love with The Dark Tower books. I've since read The Stand (loved it), but that is the extent of my exposure to King's books.
'Salem's Lot is one of the books I'm interested in reading, for a couple reasons, but one of which is Callahan's presence in The Dark Tower books. Does King do this well, pulling characters from other books/worlds and bringing them together in All-World?