Yes, 'rooms', plural.
As I was making lunch she sat at the counter telling me about how boring our house is.
"I've seen every room in the house, and no matter how many times I look, there aren't any new rooms. I wish we could add two hundred million more rooms so I wouldn't be bored."
Two hundred million is her favorite (or at least most-referenced) number lately.
The little one, like her Daddy, seems to thrive on constant stimulation. She's infinitely curious, which is probably the source of her voracious reading.
Now she needs more rooms.