What about a valance that is to your liking and then roller shades beneath them? Now don't think of the nasty roller shades that were in your gradeschool when you were a kid. There is a nice selection on Bali's website. Roller shades would hide discreetly behind your valance when you don't need it. You can get scalloped edges if you like and/or they can be trimmed with beads, braid trim or "gimp" (a braidlike trim). Bali will send you free swatches and they have a My Decorator tool that lets you "try out" the color/fabrication options with your decor colors in the room. Here is a link that might be useful: Bali Blinds Roller Shades

You should have double studs next to the window trim so install your brackets next to the trim, or within that vertical area. Then extend the rod on each side to the length you want. Once the drapes are up, you won't know where the brackets are, unless you have really large, decorative ones. Of course, doing this won't allow the drapes to open beyond the window but I would prefer this over not hitting a stud. I would try to put the center support bracket on the wall. If you mount it on the trim it's going to throw off the depth of the end brackets. Plus, I think it'll look better on the wall. If space is a problem, you don't have to use the same bracket (that's on the ends) for the center. You may want to use one that is less visible. Since there should be a header across the top of the window, hitting wood won't be a problem. IMO, you really need to hit a stud with the type hardware you intend to hang.

Think draperies hung to the ceiling draw the eye to the "void" of blank wall between the top of the window frame and the rod. How exciting is this? I would hang to the ceiling only if I had a valence which covered the top of the window frame, or had some type of "fill". Have to adapt to what your sit is, too. Have an old house with very high ceilings and steam rads under the windows. The top part of the frames are deep with decorative molding on top. Don't want to hide the details so hang the rod under the top frames, to the floor, and to either side of the rad. I use mini slat blinds for covering the windows panes for privacy.

It’s for a rental. Perhaps you are overthinking it? Generally you need to focus on tenant-proofing. Is this Airbnb or extremely upscale? Furnished?