When did you think the Warden is the descendant of Charles Walker and Linda Walker?

[Sandy]

From Chapter 28:
"Go ahead and kill me, Trout," said Kate. "But I sure hope you like to dig. 'Cause you're going to be digging for a long time. It's a big vast wasteland out there. You, and your children, and their children, can dig for the next hundred years and you'll never find it."
I guessed the Warden might be the descendant of Trout and Linda. The Warden was as cruel as Linda.

The name "Ms. Walker" first appears almost in the end of the book in Chapter 47:
She turned on him. "I'm telling you right now, if any harm comes to him, we will be filing charges not only against Ms. Walker and Camp Green Lake but the entire state of Texas as well. Child abuse. False imprisonment. Torture."