The book, "Christy" was based on the story of Christy, mother to the late Catherine Marshall. Catherine wrote the book of her mother's adventures in her youth. Some of the characters (like the doctor) are fictional. In a writing Mrs. Marshall said that the doctor was a combination of 2 people she met. In the book it looked like the doctor 'won' but, in reality, Christy married the minister.
Further on this 'historical fiction' was the book Julie, again written by Catherine Marshall. Both are wonderful books. I had the privilege of receiving a letter from Mrs. Marshall and it is in my box of souvineers!
Hope this answers some of your questions. I never did see the 3 movies - wasn't carried here in Canada - so hope to one day purchase the DVD's.
Peggy Bendell
aka
Peggy from Porcupine
http://www.mannagold.com