I live in an 1900 old farmhouse ...dining rm -i just can't figure out

First concentrate on which room you would like to tackle first.Sometimes overthinking is done instead of being productive. If it is the dining room you would like to tackle,decide is the carpet staying or going.Base paint color on your lighting in the room and keep in mine what looks like a good choice in the store it may not look like that in your home. It is always best to buy samples.

Neutral is always a good way to go. I'd choose a light beige/gray color for your walls. Do them all the same to keep consistency. Same with the floors. You can do hardwoods or laminate or carpet (whatever you prefer in your dining room and living room and tile in your kitchen. Keep the color in the warm brown tones.

Lightening up the walls everywhere will make a big difference in your rooms along with the flooring. You can keep your dining room pieces and then accent with new pictures and greenery. Living room - same thing. Get rid of the dark mustard/black/maroon colors and choose vibrant colors that work with whatever color furniture you have. Could be green, aqua, etc. Anchor the living room floor with an area rug and you're all set.

I think the most important thing is a neutral paint in all the rooms to marry the rooms together and to create continuity. After you decide on neutral paint(s) for the space, you can tackle the rooms one at a time.

Definitely paint first. Keep the rooms one color that you can live with and yet accent with different colors in the different rooms if that is the way you want to go. Get in the foundation with paint and flooring first and go from there. Who knows, maybe that is all you need to do. For the lack of light I would stay away from anything with a greyish cast or darkish colors as they may make it stay darkish. a real light gray may work though.