I first saw this film around 1967 at a children's matinée, and I remember the young girls in the audience were really getting into it, especially at the line by the grandfather, "The Phantom's a piece of wind and sky." With the advent of DVDs, I sought to find this film, but it took me about three years to find out the title, which I had forgotten, then another month to locate a copy, since it was out of print on video.
I can appreciate more now why the girls in the audience that day loved this film. It's very charming. It has a very Disney/family style, a very solid, down-to-earth plot (none of that impossible modern "Spy Kids" stuff that relies on CGI effects), a lot of focus on animals and nature, a realistic style, subtle humor, cute pieces of dialog, a well-meshed plot, a warm family feeling, and a happy ending. A film like this shows that guns aren't needed to make a plot exciting or engrossing.
Another subtlety that stands out now is that the film is educational, in the same way that Disneyland used to be educational in the early 1960s: endless tidbits of knowledge are imparted via the dialog, such as that a "hand" is equal to four inches, or that a foal should not be fed sugar since that turns the horse into a biter, or that "breaking" a horse is different (and crueler) than "gentling" a horse. It's hard to come away from the film without having learned more about horses, or without having developed more of an appreciation of horses. Also, the locations and history of the annual pony roundup are authentic, so a bit of geographical and historical knowledge is imparted, as well.
The scenery is also very nice, with a lot of sandy beaches, sand dunes, coastal pine forest, and open fields with horses running free. The small town feeling with its carnival and everybody knowing everybody else is also very nice. Other than the old-fashioned clothes and hair styles, this film seems a lot more modern than its 1961 date would suggest, and it still stands up well in this modern era without seeming excessively sweet or having ridiculous humor. There are also some gender equality issues thrown into the plot, which makes it ahead of its time. The grandparent-grandchild relationship might be a bit contrived, as is the subject matter of horses, and the boy performing a heroic deed by saving a horse from drowning, but unless one is looking to be critical, such aspects of the plot don't seem out-of-place.
This is a solid family film that should still be enjoyable for all ages, especially for horse lovers.