I added a kitchen area, plus a walk-in pantry and half of an open staircase (I will install the upper half of the stairs after building the upstairs landing).
How it all fits together (the doorway at the top leads to the living room).
But wait - there's more!
I bashed together two of Greenleaf's mini greenhouse kits to make a screened-in porch. In smaller, older homes, particularly in coastal areas with small lot sizes, it's not unusual to see porches screened in - or converted into rooms - to add precious space without changing the house's footprint. I have seen former porches converted into bedrooms, and in one case, a living room.
I originally planned on a stone floor, but wound up not liking the way it looked. My grandmother's midcentury house had a huge screened porch not unlike this one, but with a brick floor. I felt that brick walls and a brick floor would have been overkill, especially in 1:12 scale. So, a gently distressed wood floor fit the bill.