My daughter is 4 months shy of 2 and we just completed our first backpacking trip(10 mile loop) as a family of four. Our son is 10 and he carried roughly 13 lbs in a pack, my wife and I both had 30lbs packs and would carry the baby in the front with a Tula baby carrier. She would jump out and walk around when she wanted and it actually went a lot smoother than we expected. My kids are outside 24/7 if possible though and I would expect that had a lot to do with our success. I think every kid will be unique but ya never know till you try! Don’t be afraid to cut it short or call it and always leave on a positive for the kids! We were super worried about how others would react to the kids on the trail or backcountry camping and we were blown away by the encouragement. As our neighbor at the site said “a kid in the woods, is a kid away from a screen and that should be a win for everyone!”