Had to laugh at your honesty at the end. Yes, that is the first thing that came to mind – have her narrate after every paragraph or page (find that sweet spot that works for her).
Other ideas:
1. Read it aloud to her. Does she do better then? Again, I would read it in shorter sections if needed. This is especially good as she is not a strong reader.
2. Have her read it aloud to you or a stuffed animal – does it help her recall more? Some people just don’t retain as much when reading on their own.
3. Do something in between the two. Have her read a page to you then narrate, you read the next page to her and she narrates, back and forth. This way she is getting better with reading aloud (and reading in general) and if you have two copies handy she can follow along when you read or you can follow along when she reads too.
4. Do Less. If she can’t narrate after 5-8 pages then accept that. Cut assignments for each day to what she CAN handle. And do fewer books this year. It won’t be the end of the world! Better that she understand and can narrate what she is reading and go through less than read more but not retain any of it.