The HP Lovecraft Literary Podcast did a show on this story a while back, and it struck me how many movies and such this one bears a resemblance to. There's even Night of the comet, after all.
The appearance of a young white woman in the story was pretty predictable. But was also, ultimately, a fascinating consideration of the societal trope of the Aryan beauty thing in a world where the status of such may no longer mean a thing. It's easy to forget how fraught those images and associations were with status and racial tension at the time of writing, a time when the Klan was on the rise again and African American communities were sometimes threatened, supposedly to help protect the white women.
The story also serves as a reminder that, even well into the 20th century, you didn't have to visit the South or the countryside back then to see segregation, something modern folks sometimes don't always realize about the time.
I liked the opening, with its almost mysterious lower chamber the MC gets caught in and the initial confusion. Almost feels like the intriguing beginning of a different story about the lost and forgotten areas under where he is working, sort of like what Stephen King's Night shift turned into. But no, we got sci-fi and social commentary instead, which is fine too.