First off, a really high 4 stars, I did that back-and-forth argument with myself about whether it deserved 5 stars or not, but then decided it was because she stuck the landing so well that it was even a question, and for most of the book it was 3 stars, possibly 4, enjoyable, sure, but not incredible. The ending, though, it all worked (and they're the hardest part, I think).
I was a bit irritated early on that it was Mrs. Coverlet's Magicians and yet (a) Mrs. Coverlet is sent away ... again ... and (b) it's not really a magic book, the way Edward Eager's books are, and (c) I'm over the trope of "difficult person comes to look after family and makes their life a living hell", however I decided to (a) suck it up, (b) enjoy the nebulous-ness of it all, and (c) appreciated that the difficult person was dealt with rather quickly and we could move on from there.
I'll say that Nash is good at mixing kindness, decency, bad-but-well-intenioned behaviour, etc., a sort of narrative stew that makes me nostalgic for childhood and other books like this one. Yes, everyone's white, well-off, presumably straight, etc., but those were the times, and books about gender-fluid mixed-race young adults dealing with addiction and poverty wouldn't have been published, so there's no point bemoaning the culture of the day.
Lastly, I'm grateful there's no moral, other than my walking away thinking that trying to be good to one another is a good thing, and usefully, an awfully transferable rubric, useful in many situations.
(Note: I'm a writer, so I suffer when I offer fewer than five stars. But these aren't ratings of quality, they're a subjective account of how much I liked the book: 5* = an unalloyed pleasure from start to finish, 4* = really enjoyed it, 3* = readable but not thrilling, 2* = disappointing, and 1* = hated it.)