If you’re in the U.S. and have access to CSPAN 3, I strongly recommend looking for a re-run of Pamela Smith Hill’s talk on Pioneer Girl.
I have the book, which is quite good. It contains the text of Laura Ingalls Wilder’s first, previously unpublished autobiography which she used as an outline for the Little House books, along with a ton of photos and scholarly research by Pamela Smith Hill about Laura and her writing.
ETA: You can watch the video online, here. I couldn’t find an embed code, alas, and I don’t know if it’s region locked to the U.S. only.