I am rereading something I have not read for 18 years if not 20. I remembered it well enough to want to reread it, to search for it through Loganberry Books. (Contributors there seem able to access Library of Congress summaries. I haven't found that on Thomas yet, but I haven't tried for a while. Nope, I still don't see it.) Now that I've started it, I can't isolate why I liked it. I remember thinking the being abandoned and found again and the overly refined technology society vs. the hand-powered, bound to the planet one. I remembered a couple of lines: "She was a medic, and medics did not allow themselves to become filthy"; and "they [chickens] never see a human" -- "How sad"; and the pity and bewilderment at deliberately not reproducing.
Now I want more about how the culture, not just the knowledge, decayed over 500 years. I see the gaps from things left unexplained or untreated. Apparently H.M. Hoover wrote a lot of speculative fiction for young adults, but this didn't leave me curious to read more by her.