Nina Kiriki Hoffman has definitely written better books. Its not awful, it was a light, enjoyable read with a little magic and a little fun, and if I didn't know how much more she is capable of I would probably have liked it more. I think I know where she was going with this but it didn't quite get there.
Her characters are often outsiders in some way, by chance or by choice; street people, artists, runaways, backwoods tribes, musicians. Because of their outsider status they aren't that upset by strangeness, even quite considerable strangeness. Confronted with the supernatural her characters often respond with a sort of matter of fact, "okay now this is happening," acceptance. That rings very true to me, I've known people like that, and at the same time their pragmatism somehow makes the magic seem more magical.
So this book, set as it is on a film set, should work within the NKH world. Film people are certainly outsiders and are certainly accepting of all kinds of strange. But perhaps because she just doesn't know this world as well, or because there is some part of it that doesn't resonate with her "voice" the film crew never quite comes to believable life. There are flashes here and there, but only flashes.