I had an older child using Truthquest. We made some selections of books, she read the commentary, and she did the papers as assigned in the TQ guide. Truthquest was her spine.
That is the extent of my experience, but it does seem doable with the SCM book selections. You would just add in the commentary and decide if you want to do the assignments in TQ (I can’t remember what they’re called – sorry).
We use a spine periodically. I have not found one that I could stick with all year – but that’s my fault, not necessarily the book’s. I typically use them when I want to or need to cover something quickly. For instance, we just finished reading books about WWI. I went straight into the 1930s/Great Depression. Then it occurred to me that we should probably do something with the 1920s so I picked up a book on that period from the library and we’ll read/narrate/timeline through that together. Then, we’ll get back to our regular roll. Does that make sense? I didn’t to me when I just read it :).
I try not to choose too much historical fiction. For history I like to stick to nonfiction, biographies, etc, though for literature we certainly add in fiction.