If you want a Stephen King story that goes on and on, check out the Dark Tower series. (Starts with The Gunslinger) It's a totally different type of story from It and the others, but it's got a lot of creepy in it and the characters are amazingly diverse and rich. One of my all-time favorite series of books from page one to page last!
My tastes run differently with me loving all of his books, except this series. Some of my children loved it however.