The problem was that the pattern is dreadfully written.
However, once I set my mind to it and sat down and stared at the photo, the thing only took about 6 hours to complete ... including sewing all the pieces together and weaving in all the ends. If I'd only known.
Here are the pieces I'd completed six years ago, all wrinkled from sitting in a bag for all that time.
And here's me striking a pose with the finished item. I put it in the mail this morning!