What is the author's tone in the novel, The Unlikely Pilgrimage of Harold Fry?

The story's tone is filled with hopefulness though Maureen and Harold deal with tremendous demons and fears throughout the story. Harold's thoughts turn particularly dark as he nears the end of his journey, with Harold thinking about his parents and about David's suicide. Even with this, there is an undercurrent of hope that makes the reader expect that Harold will emerge to a better place in his life. That hope turns out to be true.