Building a treehouse with my kids and it's not going how I planned

Started this treehouse project last Saturday thinking I'd have it done in a weekend. We're now on week three. I underestimated how long everything takes when you have a 6 year old insisting he's your 'construction manager' and a 9 year old who wants the railing to be blue instead of brown. Progress has been slow but honestly watching their faces light up every time we add something new makes it worth it. Only thing is my back is killing me and I'm not sure how much longer I can crouch in a tree.