New Leaf Treehouse Co. constructs adult treehouses that are fully customized to fit your personal idea of a treehouse, guest house, artist studio, decks for entertaining, or off the grid retreats.
While the traditional treehouse is typically what comes to mind for children, there are many variations on this classic concept. playground equipment such as swingsets, monkey bars, slides, climbing walls, etc. can be added, as well as rope bridges, challenge elements, and zip lines.
During the design process they will work with you to create a space that fits your vision of what your treehouse should be.
Images from New Leaf Treehouse Co.: