I read a book when I was in elementary school (circa 1995) that to my recollection was about a child/pre-teen who is living in a post-apocalyptic wasteland (maybe it's a girl searching for her brother?), but then we find out at the end that it was all just some sort of simulation or video game.
For a long time I thought the book I was remembering was Z for Zachariah, but having read that recently I discovered it's not, so now I'm at a total loss.
I have an image in my mind of the book being somewhat thick and the size of a paperback, but with a hardcover, like how they used to make books that you would find in school libraries.
Would love to hear anyone's thoughts on what this title could be!