Here's a particular favorite:
Much Ado About Grubstake by Jean Ferris (who I love). I would like to point out several things about this book. First of all, it is a bargain book at amazon right now for $6.80, HARDCOVER. That is a smashing deal and this would be a wonderful Christmas present for your preteen girl or even older. If they love light romance and mystery and a western setting (I really love western settings if the book isn't about horses and shoot-outs), I think this book goes all the way up to older teens. The second thing I would like to point out is that while there are dogs in this book, it is not a book about dogs. This is not Old Yeller. The cover is just silly. Mary was very concerned about this. She didn't want to read a book about a dog. After assuring her with great passion that she would love the book, and it was not about dogs, she read it, and loved it. NOT A DOG BOOK. I love the first-person narrator in this book.
And if you like this book, try Ferris's Once Upon a Marigold, and Love Among the Walnuts.