Like you I have an awkward tv room with three double doorways, a fire place and two windows too. One thing that has helped a lot when entertaining is to have peripheral chairs next to my fire place aswell as in my three window sunroom. The side chairs are comfy yet light enough to easily pull near the main setting for football viewing, games or conversing. I would find some light yet comfy arm chairs to place in you lovely windowed nook. And a side chair or two beside the fireplace too. Move the tv a bit toward the kitchen entry maybe on an articulating arm mounted to the wall.

Dont worry about the divided floor, as long as you divide your functional groupings in the same way. That is, ok to use the smaller zone as your TV room, but only if all the furniture for that fits on that side of the walkway. Otherwise, put the TV on the wall to the right of the fireplace, and set up your seating arrangement in an L to encompass both (and maybe an extra chair or two for visitors). Then the "den" makes a natural office, etc., and you have plenty of seating in the larger space for hanging out or conversation.

Nancy, I am blown away by the idea to include elegant bar seating... I absolutely love this idea, i think it's a clever way to use the space and include additional seating!!

I think I would shuffle it back just a bit so it's not blocking the door (even though you don't use it). It'll still leave room to open and close the drapes. I don't think you'd need anything behind, but if you want something, perhaps you could put a long skinny console table (or two butted together to make a long one). If you had a skinny table behind your couch, you could add lamps and some plants.