I think "The Guernsey Literary and Potato Peel Pie Society" by Mary Ann Shaffer might make a really good movie. We had this book as the book of the month at our library book club this month, and many suggested it as a good base for a movie.
It is a very good story and has a good ending.
The books structure is a series of letters and telegrams between about twenty people, so basically most of the script would be there, it is just translating it to film. How would one translate the letters to give the characters on screen something to say.
If you haven't read the book it is a joy. Hopefully the movie would be too.