Hello all,
Just thought that I would state this even though this post is nearly a year and a half old, but did you ever stop to think that what John Cullum has absolutely nothing to do with any other King books? And, that he, Stephen King, is just laughing while you try and figure out which other book he may be trying to reference. No! SK is throwing a line with a hook but lacking bait altogether.
John Cullum lives in the Key World!! Stephen King does not write stories that take place in the key world aside from The Dark Tower 6 and 7. King writes stories that take place in the all of other infinite worlds that are a stringing along the beams of The Dark Tower. (Or, His universe.)
John Cullum is exactly what Roland calls him, Dan-Tete or Little Savior. Nothing more, nothing less. Now, what would John Cullum's initials just happen to be??? Yep... There you go.