Like Booth Tarkington, Gene Stratton-Porter wrote of and was identified with her native state of Indiana. According to the Wikipedia article about her, the novel Laddie was a tribute piece to an older brother who was killed in an accident. If so then the Joan Carroll role of the youngest offspring of the Stanton family is Stratton-Porter herself and no doubt the tender scenes when the little sister becomes the confidante and to some extent problem solver for Tim Holt in the title role is how the author saw herself in her family dynamic.
Had this film been done at Fox Studios in the early sound era no doubt the female lead would have been played by Janet Gaynor. RKO with not quite the budget and on sets that look like they were also used for their Little Men production put together a top flight cast to tell the story of the young love of two neighboring Indiana rural families, the Stantons and the Pryors.
Holt is the oldest of a large family of two sons and three daughters. The marriage of one of his sisters Martha O'Driscoll to Rand Brooks sets his head toward romantic notions about Virginia Gilmore daughter of neighbors Miles Mander and Mary Forbes. They are a British couple who bought property in Indiana and Mander is a bitter man and bit by bit we find out what's eating him. I can't go into that any more because that's a lot of the story. But suffice it to say he's just outraged at the idea of Holt together with Gilmore. This might just be the career role for Miles Mander, he's that good.
Holt and Gilmore playing a Janet Gaynor part are a fine attractive young couple and Laddie is a nice nostalgic piece about rural Indiana at the turn of the last century.