...nothing in these rooms is staying.

I am not a fan of dining rooms that have sliders like that so I like your idea of moving the dining room to the old living room. The current dining room is also quite small. Perhaps make the dining room a study/library. What style is your house? That could help us better define the rooms.
Diane

There have been some great pics for library dining rooms. Seems you have the perfect space for that. I don't care for the idea of the DR in that really small space with the sliders either. Maybe wait on that area till you feel inspired.

I love the idea of a DR /reading room/library with comfy chairs or a sofa/chair arrangement...maybe a game/work table. I will look forward to seeing what you do. I would move things in and out till it is just right. What fun to have such a nice space. c

The whole area is perfect for a library/study area. The desk can go into the smaller dining area, along with bookcases, and the larger area can contain yet more bookcases and a library table. Dining tables and library tables are often interchangeable. Don't dress it with too many chairs, and try to avoid the chairs looking "dining room". A couple of club chairs with a couple of old wooden "office" type chairs around the table should be a good mix.

As with any library, the bookcases will define the space. You'll need a lot of them, so look for some inexpensive RTA ones and use stained or painted moldings on them to dress them up and create faux built ins. If you did something like Ikea, they have doors for the bottoms, and several color options. Or, be on the lookout for several vintage bookcases, especially barrister ones and sprinkle them through the space carefully. Wainscoting, leather, brass, and lots of desk lamps on reading tables will help with the look.

I presume the kitchen is part of the original house and is therefore quite small. I would probably turn the original dining area into an extension of the kitchen. This could include a nice island with seating for casual dining, a loveseat/bookcase nook, maybe a desk.

Then of course the old living room would be the main dining room.

Yes! I'm definitely leaning toward using the area as a library/dining area and love the idea of a library table in the existing living area. Would love to hear more ideas about how to deal with the funky entry.

The furniture I will be moving into the house is a mix of contemporary/transitional pieces mixed with mid 19th century primitives. My style is Pottery Barn - Crate and Barrel - mixed with clean lined primitives.

I do have a mahogany desk and mahogany barrister's bookcase as well as an large oak bookcase with 4 glass doors (4ft high x 7 ft long). I'm not attached to the desk at all...but the other two pieces will move with us. I confess, I'm not a fan of mahogany or oak, but they are family pieces so they will have to go somewhere in the house. We also have a double bookcase in a walnut stain that has been in our office (7 ft high x 4 ft wide) The house has three bedrooms and since we have no children we can easily use some of our inherited pieced in other rooms.

I haven't invested in a dining table yet, but plan to keep it simple. I'm not a fan of carved detail or fancy legs...I like things simple and rustic. The kitchen is galley style, but opens into a good sized breakfast area. I've attached photos of the future family room and kitchen. Please keep in mind...this is NOT my furniture in the photos. The family room will have a rolled arm sofa with two leather club chairs and a rustic pine coffee table. The kitchen looks out onto the lake, so I will be filling the space with some kind of kitchen table...likely pine or walnut, but haven't decided on the shape yet.

Here is a link that might be useful: Family Room and Kitchen

Here are a few photos to give you an idea of how I am decorating in my current home. The home we are moving to is larger and is on the water. Yes, I will be keeping a most of my current furniture, but am open to parting with some pieces and to update the look and color palette to suit our new home.

Here is a link that might be useful: Current Style

So you already have plenty of spots for casual dining. Then I would plan on using odds and ends in the old dining area, creating a nice sitting room. A comfy place to sit and read, wait for cookies to come out of the oven (as though there isn't enough in the kitchen to keep you busy between batches), have your coffee, etc.

It is going to make a beautiful room once it has dining furniture and a sitting area.