Hey There: Longer Curtains don't really make your window appear bigger - it will look pretty funny at the end. Beth H. has the best suggestion...with the trim you make your window appear bigger. And if budget allows it, replace them with taller units...will make a huge difference in the feel of the room. Good Luck with your project.

I have several 15ft sliding glass doors and traverse rods which is what you need are very expensive in that size. I plan on doing lightweight ripplefold curtains. I did find a company that has the traverse rods and ripplefold tape for a good price. https://curtainrodconnection.com/ I just received my first set and haven't installed them yet but am hoping for a decent quality.

We don't have room measurements so these are general ideas to consider. Shift the furniture and rug toward the window so you create a "walkway" along the stair rails and between the kitchen(?) and the area with sliding glass doors. You said the furniture is temporary so working with what you have for now: Remove the recliner. It's a space hog, another hard surface, and there are too many chairs that make everything look choppy. Move the loveseat perpendicular to the window and place your end table next to it so it barely touches the wall. Place your velvety red (swivel?) chair in about the middle of the window. It's low which won't block your view out the window. Move your light tan and peach chairs where the loveseat is now but float them off the stair rail for your walkway. Put an end or cocktail table in between. Consider a console to the right of the fireplace and place the tv on it. The little cubby in the corner has potential for a set of small chairs or a table with chairs that can be moved to the main furniture grouping when you need extra seating. Again, these are spitball suggestions so you can see how you like the flow, spacing and function. Measurements are critical before you purchase any furniture and of course, you'll want to choose artwork and accessories that work with those selections and give you the softness you want. What is the area behind the sliding glass doors? This shows a walkway behind the two chairs:

I like the table you have in the graphic- kind of breaks up the space in a nice way. And would also be handy to use from the laundry or the fridge side. Considering the utilitarian nature of the room, you might want to keep it fairly simple with blinds or shades rather than using curtains. Keep the ceiling basic with a white tone. Depending on what kind of crafting you do, you might want that room to be as basic white as possible so you aren't throwing color on your projects. You might want/need to bump up your lighting too.