Part of my rating system depends on whether I can keep reading a book through as long as I don't have something absolutely pressing to take care of. Chasing Kate fits that requirement.
WARNING: There are frank descriptions of sexual abuse in this book. If you're seriously triggered by such, don't read this book (or steel yourself, if you want to try, anyway). This book is a quick read, but that doesn't mean it's easy reading, emotionally.
Without giving away the the plot, this story involves a young woman on a road trip with a young girl, getting into a lot of trouble, and the moral quandaries that go along with it. There's quite a bit of the "wisdom of a child" trope, but in the context of the book (how it's written, the basic subject matter, etc.) it works. There are some cases where I would roll my eyes and remove a star, but not in this case.
This book is written in the first person, so we get to "hear" Katie's internal monologues as well as her interactions with her wayward charge, Sadie, and they're the main bits of plot, whereas the outside interactions feel a bit superficial. I found myself reading for reactions rather than interactions, toward the end (though obviously you have to read what Katie's reacting to, else you won't know what's going on). This journey is obviously about Katie - the rest of the story's characters are the planets revolving in her universe. While this may be technically true of all first-person novels, in this case it's especially true. There is none of the "I couldn't have known that [character] was actually [situation, feeling, etc.], and that I was, in fact, only seeing [superficial thing]." In this book, everything Katie sees and reports, outside of herself, is largely superficial. She often makes the wrong assumption, which makes her very human and subjective.
She's very selfish, and the book doesn't try to hide that; in fact, that's driving (no pun intended) most of the plot. This book is written as though she's running away because she's hurt, and in large part that's obviously true. Then it becomes about her survival. Sadie is almost incidental, toward the end, though it's clear Katie cares about her very much. Sadie is a tool Katie uses against those she interacts with, and along with the "wise child" trope, that made the last couple of chapters a bit like cotton candy: it looks great on the surface, but when you bite into it, it's just a glob of sharp sugar.
Unlike some books, Katie does meet the end she should, and Sadie meets the end we hope. It's all very neat, but is a surprisingly satisfying conclusion.