A much better offering is Sarah Emma Edmonds was a Great Pretender, by Carrie Jones.
A note on the cover, since I only have a picture of the front (doesn't the face make you think of a Steven Kellogg illustration?): the back cover shows the back view of Edmonds, dressed in a skirt under the military jacket, with parasol in one hand as her fingers are crossed in the other. Cute, very fitting idea for this book.
And, back to one I didn't like:
This is one of those stories adults look at and pronounce adorable and clever and brilliant, while kids...lose interest five pages in. My 5yo hated it. He's a picture kind of guy, but he did not like having to figure the story out through the wordless middle, and as a beginning reader was beyond annoyed with the mud splotches. Here at the library I've had similar reactions - one little girl did like talking about the pictures and making up the story, but didn't like the pictures themselves very much - knowing her, I'd say it was the lack of color. Of course, mud is brown, and I wouldn't suggest changing that, I'm just saying it doesn't seem to attract kids the way some of Gammell's other books (Monster Mama, Timothy Cox Will Not Change His Socks) have.
Finally, swinging back the other way, we have a book with great illustrations: