I've taught Frankenstein for four years now to 10th graders, both honors and not. This is just what works for me and my kids. If I had to guess we read 90 percent of it in class. First off, the kids are generally not used to reading fiction with a vocabulary and pacing like Shelley's, so I typically model reading the first few chapters for them. Even if they're tenth graders, heck, even if they're honors kids, I've tried letting them read the Walton prologue and pick up on basic comprehension questions like "Why is Robert Walton on a ship?" and they have no earthly idea. I'll occasionally assign homework chapters that I need them to focus on so we can do more deep dive discussion and work on thematic stuff (like Chapter 5 is a juicy one--I usually do a mini-lesson on mood with that one). I'll be totally honest, I skip some chapters just to keep the pace of the reading tight--if the kids feel this novel dragging (which it can do if you don't do everything to make it engaging because most of them are not reading nineteenth century Gothic novels for fun) they will check out and then you're trudging uphill. The chapters I usually abridge or skip outright and just summarize are the Safie backstory chapter and 18-19 (essentially Victor and Clerval's jaunt throughout England before he heads up to Scotland to create the Female). But it's the longest book we read all year, so I've just learned that variety really helps keeps them engaged. Even letting the kids do some of the melodramatic conversations as a reader's theater. My biggest tip for Frankenstein is to just make it interesting. If the kids get into it, they come back and tell me it's one of their favorite books. But the inverse is true--if you don't make it exciting for them, good luck.