The best thing I ever did was put a litterbox in my office closet. I put it on the floor, and put stops on the door to keep it from closing fully - so the cats woudln't be locked in or out. It gives the cats their privacy, and the most unexpected bonus: nobody uses the closet as their junk dumping ground anymore!

It doesn't smell (I promise!) and is a sinch to clean - just open the door, bend down, scoop, close door. Since the door doesn't close completely, the cats use their paws or noses to open it to enter.

With the addition of more cats, I added another box under my desk. Its oushed back far enough that even if I stretcg out I don't put my feet in the litter. Scooping is admittedly a pain, but nobody has a clue its there (unless they are a cat)

I too was determined not to have litterboxes on the first floor. It was easy to avoid with just one or two cats... a necessity when I had 4 cats.