I've still not read all of the ERB oeuvre, but SAVAGE PELLUCIDAR definitely comes at the top of any list of "the women-led books of Edgar Rice Burroughs." It might also be the only one on the list, But Still...
By saying this, I'm not by extension agreeing with the modern idea of "equity:" that there ought to be, in boys' entertainment, just as many female heroines as there are male heroes. Burroughs wrote rousing adventures for male readers, though unlike some similar writers, he did include a fair amount of romance that could in theory appeal to female readers. I'd argue, though, that often, once ERB finished hooking up his male heroes with their romantic interests within the bonds of marriage, he sometimes didn't know what to do with them, with the obvious exception of Tarzan. So often, as in many of the serials, he would "spin off" a new hero with nominal connections to the "parent hero," and said hero would then have his own romantic arc. In the Pellucidar series, this pattern applies to both the preceding novels to SAVAGE: TANAR OF PELLUCIDAR and BACK TO THE STONE AGE.
Yet, although there is a new romantic arc in SAVAGE for young warrior Hodon (who serves in David Innes' army) and the feisty tribeswoman O-aa, technically this novel is still a David Innes novel, even though he doesn't have a major role until the latter half of the tale. Moreover, his mate Dian the Beautiful gets as much narrative emphasis as he does. Usually, even the more tempestuous ERB ladies tend to exist to test the hero's resolve. But in this novel, I would say that Innes, Dian, Hodon and O-aa share ensemble status in this novel alone. Like all of the other Pellucidar novels, the story is comprised by an episodic series of "escapes from captivity" and "search and rescue missions." Thus there's no point in summarizing the incidents, though the best sequences are those in which both Dian and O-aa are forced to serve as "earthly goddesses" to superstitious city-dwellers. Unlike many ERB heroines, these Stone Age beauties are unflinchingly violent in defending themselves. When Hodon steals a kiss from O-aa mere hours after having first met her, she cuts a slit in his chest with her stone knife, and later she stabs one of her captives to death with a spear. Dian and a male warrior have a standout scene having a bloody battle against a plesiosaur, and both females prove clever in playing upon the foolish ways of civilized people. Not that Stone Age cavepeople haven't been as dotty in previous books in the series, but we just don't see many of them this time out.
SAVAGE also offers ERB's best comical villain. This is an old man from 1800s Connecticut, made functionally immortal by his time in Pellucidar, but because he can't remember his name after so many years, the Pellucidaran natives dub him "Ah-Gilak," meaning "old man." Sometimes ERB calls him "the old man whose name was not Dolly Dorcas," which I won't explain but which I found moderately funny. Even before landing in the Stone Age world, Ah-Gilak was forced to eat from human corpses to live, and he delivered a strong liking for the flesh of his own species. ERB gets a lot of mileage from this goofy old codger, who's only an ally out of convenience but always poses some degree of menace.
Though ERB started this novel in 1942, following it in 1944 with LAND OF TERROR, the last in the series, for many years it was not fully extant. To explain, I'll content myself with linking to this excellent writeup of the novel's history and conclude by stating that SAVAGE stands as one of the best books in the series, eclipsed only by the TANAR novel. Oh, and though this is a David Innes novel, I deem it a minor crossover because it does include a brief scene with Stellara, the female mate of Tanar-- who exist in their own "sub-universe" rather than being part of Innes' regular cosmos.