I would have the chandelier electric box moved to center of entire space and do a long rectangle table...you could alsodo two smaller chandeliers over table too!

I don't think it is overly large, The room is long, but narrow. I know my dining room table is often opened up to accommodate 10. You need the length to open up the table and have a buffet and room for extra chairs. I would also center the chandelier and move the buffet to the wall to the (i think) is the kitchen doorway. It looks now that if you open up the table it would be to close to the buffet for people to sit.

Narrow is the operative word. It is also a hall from the stairs to the living room or Kitchen? I think the chandelier is where it has to stay. A seating area could be done in the space to the front of the room. Maybe use some great captains chairs until you are entertaining then just pull them up? A side board for serving dishes/formal service would be very useful. I agree a table that can be expanded to fill the space would be fabulous for entertaining. The only item in the previous owner's home I don't care for is that bench by the window. It looks like an old iron bed. I think you can do better.

What are the dimensions.