In a word, The Distant Hours is about closure. The novel treats the issues of family, marriage, and courtship especially, and the main climax of the novel comes when Edie is finally able to settle all the debts of the people between the house and her own family, and she makes it so that everyone who was effected by what happened to finally move on with a sense of closure and resolve. In a sense, the story is like a ghost story, but the ghosts are memories of people from yesteryear.
The novel also addresses the problem of loneliness and privacy. By allowing shame to fester, Edie's mother feels unable to discuss what happened all those years ago, and that's not helpful to Edie or her mother. But when Edie finally makes it her business to find out the truth, she finds that the truth is available, and she wins a bounty for her family in the form of closure.
There is also an element of creative struggle addressed because Edie is a young-ish professional writer whose story interacts with other intellectual characters, including one of her favorite writers.
Overall it seems that The Distant Hours is an attempt to show how much energy it takes to overcome tragic situations instead of dwelling on them forever and suffering them alone in the privacy of one's head. It takes team work, it takes honesty, and it takes a disciplined resolve to move on.
