Maybe a 9 x 12

I like the denim color of the sofa. Not sure that I would go darker.

I would place the rug parallel with the fireplace.

Is the sofa teal or blue?

I would orient the rug with the couch so the long side of the rug is parallel to the long side of the sectional.

Sorry - the sofa is our only new piece here that we're building everything around. It's denim blue. Walls are cream yellow. The TV stand, end table and ikea chair will eventually be replaced by something more grown up. There's also a kiddie play area in front that will take up space and add nothing to design.... But hey - that's why it's a family room.

So, 8x10 or 9x12 long side parallel to long side of sectional?

In front of the fireplace (long side to the fire place stretching side from side).

It's just over 6 feet from the edge of the fireplace to the front legs of the couch. About 4 feet along the short side of sectional. Do I need to extend the rug all the way to the tv? If not, will all the wood look silly naked?

Also, what colors should I get to not be matchy matchy w blue and yellow?

You don't need to stretch the rug all the way to the TV. I will not look weird if you leave that part of the wooden floor uncovered.

http://www.westelm.com/products/key-wool-dhurrie-horseradish-t580/?pkey=crugs-flooring&cm_src=rugs-flooring||NoFacet-_-NoFacet-_--_-

http://www.westelm.com/products/recycled-denim-jute-rug-t011/?pkey=crugs-flooring&cm_src=rugs-flooring||NoFacet-_-NoFacet-_--_-

Is it possible to move your sofa forward a bit and the create the play area behind the sofa. Using the book shelf, chair and play rug. Trying to bring the two focal points (fireplace and tv). Into a working unit

Gina - that was the original plan. However, the kitchen is in the front, and I can't see the kid from behind the couch. It's utilitarian to have it in front but it works for us...

I'm thinking 4x6, long side to long side of sectional which is centered to the TV.

An interesting ideabook for you, follow the link under the picture:
https://www.houzz.com/magazine/11-area-rug-rules-and-how-to-break-them-stsetivw-vs~222609

I'd love to know where to purchase the denim sofa/section? Thank you!

Jordan's furniture, in MA. The manufacturer is Jonathan Louis, the texture is "heavenly" and the color is "sapphire." Texture up close attached, but the color is more like the first picture. Not very $$, $2000 w everything, but some feathers are shedding out of the cushions...