What are your needs for the WT? Looks, privacy, light filtering, block out? Since it's the dining room, a pic might help to visualize the space and your own style. I have 2 sliders backyard facing. The one in the kitchen/family has no treatment and I prefer it that way; in our master bedroom we did layered treatment with a double traverse rod with center opening pinch pleats on top and sheers below for light filtering/privacy--above that I plan to hang a valance when DH gets around to it. As I wanted the center opening, I took them about 15" beyond the door frame so when open they stack back behind the door. Before I had them all go to one side, but I like the symmetry of this arrangement better. If you do decide on a fabric treatment you can tie it in and dress up the wood blinds with a coordinating valance or roman shade. There are other options for vertical blinds (some with sheer material in between), bamboo, etc. Check out the JC Penny website for other options. Here is a link that might be useful: JC Penny draperies

Thank you all for your opinions! @ Kayz5, These windows are facing the street/front but the main entrance to the house is in the back. A driveway takes you to the "back" where there is a main entrance door. The doors on the front of the house would not be used so much in winter. I will have to think about your suggestion of mounting close to the ceiling. That could work except that I had hoped to leave the trim unobstructed. @tibbrix, yes we are in Maine and that is a view of Frenchman's Bay. I am leaning towards the white minimalist cellular shades (which actually are rated for the highest R value). I plan to investigate those comfort tracks, but don't know if I'm going to like the looks of the tracks. I don't have the wall space on either side of the curtains---the few inches of wall between the window trim and the door trim has light switches on them. Annie sure did supply an array of possibilities! I have searched HOUZZ umpteen times looking for "window shade" ideas and none of these examples showed up! There are some similar to my set up. Thanks, Annie. I wish a knew a good decorator in the area....

What purpose would the door covering serve? Privacy? Light control? Decorative only? I would never use vertical blinds--I just don't like them. So that leaves either curtain panels on a rod with enough fullness to cover the entire span of glass, or some sort of Roman shade installed high up on the molding or wall (if you need privacy and/or light control). If it's decorative only, then curtain panels that cover part of the glass/frame, but that can be pulled back far enough to open the door.

Not sure if it would work for you, but if it's really the only window you actually NEED to cover, perhaps an outdoor mounted solar shade could work. I put one outside my west facing dining room window - it's remote controlled from inside the house. It blocks the sun, but you can still see the view outside. Mine is mounted high up under the eaves, so it's nearly invisible from outside. I got mine at Costco and love it. Sunsetter