Sean Rideheart shows up late in the narrative. His name, Rideheart, and his white hair make him a sort of knight in shining armor for the Stitch and B**** club, even though they think he's kind of a Southwestern carpetbagger at first.
FYI, carpetbagger doesn't mean that he's some kind of rug thief, tiptoeing through people's living rooms at night with nefarious intentions. It means that people think he's just some jerk Northerner showing up to make money off the Southwest only to then get out of Dodge. In fact, he's come to Grace specifically to help the Stitch and B**** ladies translate their success in the world of folk art into action on the mine.
Rideheart recognizes that the ladies should be able to get Grace on the historical registry and thereby stop the miners from redirecting the river. He helps them do it, which is interesting—because even though a lot of this novel is about standing up for what you care about and doing something with your life, ultimately the women of Grace can't get it done all by themselves. They need Sean Rideheart. They need him to notice them and bring his expertise on historical status and folk art in order to achieve their goals.
The point is that even if you do your best, you can't necessarily achieve your aims alone. It takes a lot of people, all doing what they're good at every day, to make the world a better place.