A reader of AICL wrote to ask if I've seen Squirm by Carl Hiassen. Published in 2018 by Knopf (Penguin Random House) here's the description:
Some facts about Billy Dickens:The review at Kirkus tells me that, in Montana, Billy learns that his dad--Dennis Dickens--has a new wife and that Billy now has a stepsister named Summer. They're members of the Crow Nation.
* He once saw a biker swerve across the road in order to run over a snake.
* Later, that motorcycle somehow ended up at the bottom of a canal.
* Billy isn't the type to let things go.
Some facts about Billy's family:
* They've lived in six different Florida towns because Billy's mom insists on getting a house near a bald eagle nest.
* Billy's dad left when he was four and is a total mystery.
* Billy has just found his dad's address--in Montana.
This summer, Billy will fly across the country, hike a mountain, float a river, dodge a grizzly bear, shoot down a spy drone, save a neighbor's cat, save an endangered panther, and then try to save his own father.
From what I can see in the Google Books preview, once Billy gets to Montana and to his dad's house, he meets Summer. Her last name is Chasing-Hawks. A few months after Summer's mom and Billy's dad started dating, Summer and her mom moved in with Billy's dad. Billy asks "Was it hard to leave the reservation?" Summer replies "Life on the rez can be...challenging?"
I'll see if I can get a copy, and if I do, I'll be back with a review.