I liked this movie! *SPOILERS*
It's hard to find but I taped it from the Turner Classic Movie channel a few years ago.
The old saying "you can't go home again" is true. Andy Hardy had finally outgrown Carvel. I liked seeing him in the role of husband and father and not as an immature teenager. Lewis Stone, the actor who played "Judge Hardy" in all but one of the Andy Hardy films, had died and so his character was dead too. I assume Marion's husband had also died since divorce would have been unthinkable in the Hardy family! Marion and her son probably lived with her family so they could all be under one roof for the movie. Marion was only in a few scenes, and it would have detracted from the main plot to show her and her son in their own home.
And Polly Benedict? I once read that Ann Rutherford, who played "Polly", had been asked by Mickey Rooney to be in this movie as his wife! Ann didn't want to do it however, and told Mickey that most people didn't marry their high school sweethearts and she didn't think it was believable. Over the years it would be natural for Andy and Polly to lose touch, especially if she married someone else. When I see the movie I just assume that Polly is long since married and moved away.
I'll bet Andy met his wife Jane at college! After all, he returned to college after serving in World War II. Can't think of which movie it was, but he was in love with a girl named Kay, who married someone else. As to how they wound up in California, it was the Promised Land back then.