Also in the Stuart Series is Prince Across the Water. It takes place in Scotland, of course, and tells the tale of a young boy who sneaks off and joins their equivalent of an army to fight for the "Bonnie Prince Charlie" in order to restore his father, James Stuart III "The Old Pretender" to the joint English and Scottish throne. He had been replaced by his sister, Mary, and her husband, William of Orange.
Unfortunately, I hadn't read anything about this throne/succession problem before, and Yolen didn't really explain it well enough for me. So heaven knows a (pre)teen would have no clue what the Scots were fighting for in the first place. Same as Queen's Own Fool, I enjoyed the book, albeit less than others, but would not recommend it to non-nerdy youth. And how many youth are historical fiction nerdy? So while it did make me want to read about the royal Stuart family and the Orange succession, I didn't really find Prince Across the Water to be a complete success. However, the story of the prince was background to the story of the young boy, so from that perspective, it was pretty good. So, mixed feelings. I don't regret reading it, but I'm not certain I would recommend it.