Guests on Earth starts strong but flounders toward the middle, thumping slowly toward an unsatisfying ending (all of Lee Smith's books have crappy endings). It reads like a big gumbo of things the author finds interesting: mental health and the treatment of "wild women" in the mid-1900s, southern belles, mountain music. I don't think the soup comes together to form anything particularly memorable. The narrator is interesting, at least--big improvement over the narrator in Call Me Zelda--and the portrayal of Zelda herself is probably fairly realistic, but what is left to say about her at this point?
I would have enjoyed more of Evalina's life in New Orleans and less of the increasingly tedious Highland scenes, but so it goes. On the plus side, nobody in the book is said to have run off with a radio DJ (a throwaway fact about minor characters in 2 or 3 of Lee Smith's other stories).