We have a similar situation: Foyer opens to Dr; DR opens to Sun Room. From the front door you can see all three rooms. What I did with the area rugs was transition through proportion of color. We also made sure the rug colors in each room picked up the wall colors from the other rooms. The Foyer (painted Stuart Gold) rug is predominantly red. The DR (painted Confederate Red) rug has quite a bit of black with obvious touches of red, gold, olive and terra cotta. The Sun Room (painted Olive Branch) rug has quite a bit of terra cotta with a black edging and obvious touches of gold, olive and cream. The patterns are somewhat similar but in no way do they look to be part of a "rug family". Does this help?

@Lil S I was going to use a runner initially. But, I thought it shouldn't block the stairs or entrance to the kitchen. I guess I was thinking too much. I've never had a long hallway before, so I was stumped! I appreciate the feedback. @Karen Rose: Apparently, I was thinking way too much about this and should have went with my first gut. Ugh. Thank you so much! @groveraxle You are awesome for proving a link. I was looking on Wayfair and Overstock and couldn't find a runner longer than 13 feet. Since the 22 foot runners are only 2' 3" and wouldn't cover the opening of the front door. I think a indoor/outdoor rug and then a 16" would work, Yay

I think this may be a Coco Chanel moment “Before you leave the house, look in the mirror and take at least one thing off.” I love your space, but there is a lot of large scale furniture. I would remove the teachers chair and one of the single chairs. Place the remaining large chair at the empty end of the sectional sofa. This is now your conversation pit I would move the piano back where you originally had it and bring in two dining room chairs and place them by the corner windows across from the piano. This is now the music area. I played organ when I was young and at least twice a week my dad would suggest that he and my mom have their coffee in the living room while I played organ for them. I came home every day from school and immediately went to practice, never knowing if this would be a night where mom and dad would want to hear what I have been working on. It was a huge incentive for me to do well. I see your space being able to provide that exclusive attention that was so important to me when I was young.

Generally, I try to think of area rugs as islands or anchors for the various furniture groups within the room. Each group has a function and gets it's own island. In your instance the room is pretty large and most of the furniture, as arranged, could be considered one group, so maybe just go with the single large area rug. The 10 x 22 rug seems to be the most balanced for the room since it would leave you 2' of exposed flooring on all sides. Consider also the projection of the piano it's far end as to where that would terminate on the edge of the rug. I hope this helps! Also, if you have some painters tape handy, measure out where the corners would be on the floor, tape it down, and live with it for a bit to see if it feels right for the space before you place the custom order. You'll have a better idea of what it will look like and, hopefully, ease some of the anxiety related to the project.