If I had the space, time AND money I would build a tree house.
Like this one, I would give it easy “access”, such as building a lovely bridge.
I would make sure that my tree house had a lovely view of a lake and / or, a babbling brook.
My tree house would have locks on the doors and windows, so the trolls could not enter. (Trolls are such nasty house guests.)
I may even put in secret passage ways, with confusing twists and turns to confuse my enemies. If it looks like the above one, I may have to charge admission for those who want a quick “peek” !
If I had LOTS of money, I might build my tree house out of stone or cement to keep marauding monkeys out of my pantry. Last I heard, monkeys can NOT chew through solid objects.
If I want to drive someone CRAZY, I will build a round tree house and then tell then to sit in a corner. (Mean, but effective.)