This book was about a girl who lived in a post nuclear society where they worshipped nukes. She was considered ugly, gangly, and tall - and had telepathic abilities. She is accused of witchcraft and she and a young boy have to escape through a wasteland filled with mutants. There are people from a more advanced society who are telepathically in contact with her and trying to rescue her and the boy.
I read it circa 1980.