I was faced with that exact situation while in the Navy. I had a 2 bedroom apartment and used the spare for scrolling. I didn't use any kind of dust collection on the saw, for me personally the vacuums are too loud for me to concentrate on my cutting. I know this is contrary to what many think, but for me the saw itself really isn't that loud. I would cover any furniture with sheets to keep the dust off and I had a small fan blowing across my face to keep from breathing a ton of dust. For me the dust in the air and on things was quite minimal and a quick clean up if people were coming over is all it took. I had made a small "bench" for the saw with a lip around the perimeter to catch any dust from the cutting and keep it from the floor. And if I needed to do any sanding on the project after cutting I would wait for a nice day and sit out on the deck to do the sanding.
I still don't use any dust collection on my saw, the noise from the vacuum is just way too annoying for me to concentrate and enjoy the cutting. I know that most everyone will say that's a bad thing, but with a small fan and a mask if needed I'm doing OK! My "shop" these days is in my basement, I have a dust collector for my table saw and planner and anything else that makes a mountain of dust, just not the scroll saw.
Chris