Where I was getting lost was in failing to understand that there is a real difference between getting the outline filled in and writing the book. Right now I have two TP documents side by side on my vertical monitor. The second is just a copy of the first one. So, as in Scrivener, I have two views of the same document side by side. I am making good progress this way with something that was starting to overwhelm me in Nisus.
I love the folding text feature in TaskPaper.