King himself has always blocked any use of his work for haunted houses and events like HHN. No one seems to know the reason.
That can probably explain why the hell The Dark Tower took so long for development of the film to go full steam..
Years ago (pre-TWD), an extensive survey described a Stephen King "take-over" of the event. Nothing ever came of it tho--who knows if lack of interest or inability to come to terms.
Strangely enough, I have a slight feeling that if we ever get King, it will be next year to coincide with the reboot of IT..perhaps i'm wrong, but it's just something that would potentially make sense (although it matters on if the new reboot has enough material to garner a house..).