Both of the ones I've finished since then are by Ralph Henry Barbour, as well. They've all been set in New England/upstate New York, so far as I can tell.
The Lucky Seventh (1915) is a baseball story about teenagers. Dick Lovering (sometimes called "Dickums"!), team manager, is on crutches due to a hip defect; he's the hero of the story, all-around smart and honorable, but gets random condescension and pity nonetheless. The rich kid, who isn't that bad, just a little selfish, is redeemed by the end, if having more friends is redemption; his rich dad, who wanted to sell the school baseball field, is redeemed once he sees the awesome-ness of baseball but he tries to teach one of the pov characters to be more mercenary. There's a kid who stutters - nicknamed "Fudge" - all his friends like to get him excited so he'll stutter, to show affection (?). Fudge also writes stories, which are over-the-top melodramatic, but by the end he's writing more realistic stuff. Vintage medicine: Rich kid Morris breaks his leg in two places, and is bedridden for 6 weeks. Women: Gordon's mom, barely seen but who appears to be from a sitcom of the 1950s; the ineffectual mom of a kid Dick is tutoring; Morris' mom, who won't make decisions but gives them to her husband; and Morris' little sister, who is okay because she likes to play tennis and supports the baseball team.
The Crimson Sweater (1907) covers a range of sports, beginning with football and ending with baseball, with some cross-country running and rowing in between. And of course, lots of lessons about Sportsmanship. Women: a tomboy, aged 14, nicknamed "Harry." She has many pets and volatile emotions, but can skate really fast. Her mother appears very briefly in passing. Vintage ouches: teenagers acting as blackface minstrels in a show; cultural appropriation of Native American tribe names when camping; mild teasing of the kid who is slightly heavier than the rest, but still plays sports.
Currently, I'm reading an Angela Brazil novel, The Jolliest Term on Record, which is rife with equal-opportunity racism and classism, which I am noting down for your delectation.