S.H.
Use a fabric shower curtain, and curtain rod with rings, to make the fabric "door" for her storage room/play house. Just get a pressure mounted curtain rod, for the doorway, to hang the fabric shower curtain on. Easy.
Get a cute area rug for it to lay on the floor.
Get cute fuzzy pillows for that "room," for her to arrange in there and hang out.
Get a cute battery lamp or light, for it. But I assume, that storage room already has a ceiling light in it?
Or get a Japanese lantern, type "lamp" to put in there.
It will create, ambience.
You do not have to buy a "play house" for in there.
Or, get from Walmart, a toddler play tent. That she can play in, in there.