I finished the strap and put the whole thing together over the weekend. Of course, as with everything I do, I didn't bother to do a gauge sample, so my piece was 5 inches shorter and 2 inches narrower than the pattern, which then necessitated a whole lot of math on my part. Math and I don't get along at all, but it appears that I was successful in figuring it out.
Hopefully this coming weekend I'll travel to my mother-in-law's house to do the scary felting.