Make the outside of the indoor "playhouse/room" to look like a real house. I would only of dreamt to have something like this as a kid. My kiddo and future kiddos deserve a kickass room they would be proud of.
Key holders are an essential feature in your home if you tend to lose your keys. Many of us have lost our keys a number of times, if only we had a place to put them once we got home, this is where Key Holders come in.