We've been looking at houses with guest houses/casitas for my mom. We saw an interesting one last weekend. The guest house was a former tool shed that had been converted by the architect owner into a really interesting space. Although it might not be at all what you want, it was an interesting exercise for me in thinking outside of the box. Every room is a pass-through room, with the flow something of a serpentine through the rooms. It has 862 square feet and is based on a grid of 9' squares (sub-optimal, but he was working with the cards he was dealt, it appears). I thought to post it here because it has no true hallways. We would consider making one tweak -- a door from the Office Space into the bedroom, so that the "ante room" or whatever on the way to the bedroom could be its own private bedroom and/or storage area for the main house that is "separate" from the guest house. The spiral stairs go to a sleeping loft over the bath and kitchen area -- large enough for a queen mattress.

Post pics of your room and a to scale floor plan

Take advantage of the wall and build in storage and a continuous counter for two chairs. t

The home office space isn't very large. When you say you don't need all of it, what do you need? Just a desk? No shelving? What else do you want to be able to use the room for? As for the living room, it sounds like you already have a good arrangement. What is it that you don't like about the current arrangement?