oh, a thought just occurred to me: you COULD always have the first room be a living room, then move the kitchen over to what used to be the living room, add a wall betwixt it and the sunroom, and let the sunroom be a dining room. That would be acceptable IMO. But then your sunroom furnishings need somewhere to go. That's where adding an extra floor comes in handy.
(I plan to piece together an extra floor from bits and parts I see on ebay). No way am I going to buy the actual extra floor set that goes for 3-digit figures these days.