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.
DIY IKEA Hacks for Kids' Rooms: GRUNDTAL magnetic knife rack repurposed as a wall storage for toy cars.Ikea magnetic knife rack for car storage. Keeps the favorites handy and off the floor (saving my bare feet in the dark).