I intend to promote our juvenile fiction to adults more often at my library. Some may want to revisit favorites like Beverly Cleary and Judy Bloom like you mentioned. Nostalgic re-reading can be fun. There are also newer books published since I was in that age range that strike me as modern classics like the Lemony Snicket books.
Rereading some of these modern classics esque books has been such a joy. I remember so much and it was fun to connect or reconnect the dots of the story. Such a joy, and some parts of the book were better as an adult -- being able to relate to the older characters as well as the young ones. I think other adults would find great joy in it as well (and its so quick!)