The Question and Answer section for Flannery O'Connor’s Stories is a great resource to ask questions, find answers, and discuss the novel.
The Grandmother remembers an old plantation that she thinks used to be in this area. Bailey does not want to take a detour to go find it, so The Grandmother makes up a lie about how there are secret doors in the house with hidden treasure; this...
From the text:
The daughter, a large girl in a short blue organdy dress, saw him all at once and jumped up and began to stamp and point and make excited speechless sounds.
I think she is trying not to get killed. She flatters him by saying he is not of "common blood". She also tries to convince the Misfit to find Jesus.