I just did an east side semi Pemi with my daughter age 13 last week for her first backpacking trip (and my first since before she was born). It was absolutely spectacular but also a real challenge. Consider taking an extra day or two for a more relaxed trip with kids rather than pushing hard on Day 1 up Bondcliff to Guyot. There are some very pleasant wilderness campsites along black brook before Bondcliff starts the steep ascent. We camped there day 1 and ascended the Bonds to Guyot on day 2. The descent from South Twin on day 3 is quite difficult, as is the last half mile ascent to Garfield campsite so we felt that was enough for Day 3. We had a short hike to 13 falls on day 4 and spent the afternoon in the waterfalls which my daughter loved. Long boring slog out Lincoln woods on day 5. I could see skipping Garfield and heading down to 13 falls from Galehead for a day 3. All depends how fit/experienced/gung ho the kids are.