The platform is roughly 8 feet by 11; the treehouse footprint is 6 feet by 9 feet, including the covered porch area. The inside is 6 feet by 6 feet, and in the middle the ceiling is about 6 feet as well (e.g. adults can stand up, sort of, in the middle).
How safe is a high treehouse?
It's only as safe as you make it. In my case, once you're inside the rope ladder, there's no place outside the treehouse for kids to go. But every additional foot high you build a treehouse adds risk; plan accordingly.
How much did the treehouse cost?
All told we spent right around $3,000. A big chunk of that (well more than half, actually) was the choice, last-minute, to go with panelized playhouse components, which saved me a ton of work but were more expensive than simply frame-building. On the upside I have a lot of leftover really nice cedar lumber from it for future projects.
Is it legal to build a treehouse?
It depends, and it's different in almost every city or town. Read your local building codes, look for other tree houses in the neighborhood. Ask first.