Prequel it is

I started on the prequel story. It's interesting trying to decide how much exposition I need to make the story make sense to someone who hasn't read the novel. In order to tie the story in the way I want to, I do need SOME background from the novel, but trying to incorporate it in a seamless way is proving to be a little bit more difficult than I thought it would be. I don't want to put too much in because yawn, but I want the story to tie in to the novel in a significant way.

I'm currently reading The Sisters of Eluria by Stephen King, a prequel to The Dark Tower saga. Having read the whole DT series, the references and language used are familiar territory for me, but I can see how he tried to incorporate that info. without hitting the reader over the head with it - the question is, how much would make sense to someone who hasn't read the series? Of course, the difference for King is, who cares if they haven't read the series - there are enough people who have read it and will understand, as opposed to my story. Well, maybe one day people can undig the story as a buried treasure...