Darren, I agree with you that the movie is pretty much a scene-by-scene filming of the book. But the one final problem--for me--with the difference between the two is the book's description of what happens as Marian opened the door to the grand lady's room for the last time. As I recall, the images and descriptions in the book as to what happens that creates the new grand lady (I use that term so as not to spoil the book or film for others) are skipped over in the film. And even the screenplay, which I just checked, omits this fantastical chain of events. I still think this was chucked to avoid cost overruns on special effects, but in the end, there are many wonderful scenes--and some grand camp!!- in the film.
Now, back to my topic, would anyone like to cast the DS actors in a parallel time version of this film? LOL.
Brian