Rosemary as you know I don't make a habit of rereading books as this is no exception. I'd read the Donaldson books about 15 years ago and had no problem with picking up where the story left off thanks largely to the Intro. It's only about 10 pages or so long but just read it a few times and when you're reading the new book and things wil start to sink in again...
In a sense this first book is the start of a new story so it doesn't matter if you can''t rememberr all the details of the previous works as long as you have a genreal idea of what happened before and just enjoy the new book which after all is the start of a new series/story arc.