Thuvia, Maid of Mars. Thuvia herself is a McGuffin- she's onstage quite a bit, but only to drive the plot (and all Martian males wild with desire for her). She's no simpering creature, though, and she's not prone to fainting the way Jane Clayton was- toward the end, she shows a prowess for shipboard cannons. But the story is really about Carthoris, son of John Carter and Dejah Thoris, and his journey to rescue the woman he loves. It's a wild adventure, as are all of the Barsoom stories.
The Chessmen of Mars, which features Tara, daughter of John Carter and Dejah Thoris. I've only just started, so she may be McGuffiny as well (given that I'm only on Chapter 3 and she already needs rescuing), but she's a strong character, and I'm liking her. And while Barsoom has lots of weird and creepy creatures, the headless humans with spiders on their shoulders may be the absolute creepiest.
After setting Fool aside, I took up with Graceling, one of Amazon Kindle's Daily Deals, and I'm glad that I did. The story revolves around teenage Katsa, a girl whose different colored eyes signal a Grace, a strange talent. Some Gracelings can cook, others can hold their breaths for long periods, Katsa can kill. She's an unwilling assassin for her uncle, the King, yoked by her unnatural skills and the non-Graceling population's wariness of those with special talents. I'm not very far into the book yet, but I'm totally hooked.
After I finish with the Spider Heads, I think I'm going to give the listening a rest for a bit (I've heard something like 14 Edgar Rice Burroughs books in a row), and do a little watching. I can watch streaming video on my Kindle Fire, which fits perfectly on the little treadmill ledge. I've decided to start with Downton Abbey. I'm pretty sure that'll make exercising a bit less tedious.