Leading off on Mark's comment wrt how much space O scale takes, my train room is 11'8" X 12'8" and one simple around-the-walls loop is what fits nicely. Granted that I am limited by a 42" high knee-wall which pretty much precludes a twice-around up-and-over track-plan.
Looking West, leaving room for a futon guest-bed means a single track on a narrow shelf along the North wall:
Facing South. Even modest O scale structures use a lot of real estate:
Wow I really like what you did with the space. I visited a forum member, TexSpecial in Portland years ago and he had a similar room. I was impressed with the amount of running he could do and how it incorporated into the room. Sadly he hasn't been on the forum since 2015.