Does any one know what film this was?

I think it was made around the 80's, it was a psychological thriller about a popular horror author whose creations actually came to life in a small town. Several of his readers went down to said town. I believe that Stephen King was in some way involved in the production, but I'm not sure. I remember one particular scene in which one of the readers was driving down a long and virtually deserted high way when he began falling asleep, and then a strange old woman on a motor cycle veered out in front of him and woke him up. If anyone knows what movie that was, your answer would be much appreciated!