Oh its possible without the backpack, but for sure a long and tiresome day. The locals seemed to take it pretty well though! But I would say if you're not living in that environment it's definitely not the best venture for the family HAHA
It says 9km at the bottom, but turns out they measure the vertical distance and not the foot distance, so it was approx 22km each way - A local later explained it to us when we rolled up to camp at around midnight! oh well it was well worth it looking back, but there were certainly some painful arguments along the way. The happy snaps were a thing of the past on the sleepless return trek.