I'm finally making progress on chapter four.
The problem, as I always suspected, was the inability to edit effectively on the AlphaSmart Dana. Even with the bigger screen it was difficult to (no, impossible) to view large sections of text and scan up and down through the pages.
The eventual solution, which I had discarded out of hand early on because I had decided it was impossible (even though I had never actually attempted it), was to use my laptop.
While I'm not enamored of laptops--they are fiddly, difficult to see, unwieldy and have abysmal battery life--I have to admit this works well enough. I just have to keep the laptop charged up (which isn't difficult, it's plugged in all day) and leave it on 'sleep' mode. I also started carrying it in the document pouch instead of strapped into its rightful place. That way, I can just take it out, open it up and start typing. Well, almost. But close enough to actually get some work done, and that's all that really matters.