treehouses

"Zoning restrictions might be a huge headache, however."

I know of someone who enjoyed building treehouses. Built a whole treehouse complex.

The problem wasn't so much zoning - he simply did it out in the country where zoning wasn't an issue. The problem was the building codes. Despite his tree houses being quite sound, they required him to add all sorts of reinforcements that kind of made them not-treehouses.