Kirk,
You have mentioned that you want to prepare a manual. My suggestion is that you set up a "wiki" and have your community of users go to work.
I am confident that the members of your user community would be willing to share what they have learned with newbies like me, and I am also confident that there is a lot of knowledge out there distributed among these members. Why not tap this resource? One advantage might be that your users see your program from the outside, and so perhaps they can see it from a different angle that might be valuable to other users.
You could provide a structure of topics, sort of an outline or table of contents for the manual, and let the group have at it. And then, when it looks reasonable, you could freeze portions of the text, edit them, and post a final version.
I suspect that this would save you a lot of time, and perhaps it could produce a good product. And if it doesn't, you could learn something from that.