You are right that curtains are the hardest part when doing a mid century modern look. I would go with a simple linen or raw silk curtain, something with a little texture.

Your house doesn't seem to lend itself very well to the MCM look though. And MCM doesn't usually blend very well with things like your traditional chandelier.

Here's a little light on the subject:

Some simple linen drapes nice and full would be great and IMO that pine painted will make all the decisions much easier . I have a MCM ranch and I removed all the pine and do not find it hard to have that MCM vibe without it.I do agree the only MCM thing I see is the sofa at this stage and yes the same drapes in the DR would be nice.

When was the house built? Is it mid century but with traditional details? A lot of houses were sort of a mix of mostly traditional with some modernist details. I worked out a house that was midcentury "colonial revival" except that the living rooms had floor to ceiling picture windows, the bedrooms had clerestory windows on the bed walls and the bathroom was indistinguishable from that of an MCM house.

Most houses were (and are) a mix of styles and I think you could probably create a reasonable mix in your house.

I like simple linen suggestions. If you like a bt more pattern/color, and yo u're ok with ( mcm) patterns-you can look into Orla Kiely or Marimekko..the vibe is very much mcm and will work nicely with pine

several examples:

https://www.amara.com/us/shop/brand/orla-kiely/curtains

https://www.curtains-2go.co.uk/curtains/20958/two-colour-stem-powder-blue.htm

https://www.finnstyle.com/marimekko-curtains-valances.html

ombre can be cool

https://www.allmodern.com/decor-pillows/pdp/shades-ombre-room-darkening-rod-pocket-curtain-panels-dnty1159.html?piid=14917755

https://www.allmodern.com/decor-pillows/pdp/shades-ombre-room-darkening-rod-pocket-curtain-panels-dnty1159.html?piid=14917760

(they've four colorways)

or smth like this..with just a bit of texture and subtle geometry

https://www.anthropologie.com/shop/tufted-patricia-curtain?category=curtains&color=006

these are much busier..but are a statement, in their own way, and might play well with your kitchen as you describe it

https://www.anthropologie.com/shop/tufted-makers-curtain4?category=curtains&color=018&quantity=1&type=REGULAR

another black and white design if you're into repeating it

https://www.anthropologie.com/shop/shayla-curtain?category=curtains&color=001

or that's more subtle gold -the background will blend with your pine better, and will be great partner to your gray.

https://www.anthropologie.com/shop/tumbling-diamonds-curtain?category=curtains&color=016

in short many possibilities where you can marry your preferences and givens together..they'll give a different feel but I believe all will work

Thank you all so much for your help! I think linen would look great too! The house was built in the 50’s, and your right not all the furniture is mid century I am slowly replacing everything as I can. So now the look is definitely more eclectic. The upstairs of the home is very original, mid century, the downstairs much more country which I am trying to get away from. The chandelier is part of the dining room, that is getting replaced with this fan

https://www.lumens.com/artemis-ceiling-fan-by-minka-aire-fans-PAAAAAGONAAJPKCK.html#cgid=11040&&tileIndex=1

would you all recommend painting the paneling or taking it down (I am pretty sure the paneling is just a add on and can come down)

I think painted paneling can become nice subtle element-texture but same color as walls

you can take it down too of course, if you don't feel it adds to your vision of the house in any way

On Retrorenovation blog your house would be called Midcentury Modest probably. Meaning that it is not full on modernist. But you can still use furniture inspired by the period