I use to live in a studio apartment. I had my enlarger permanently on top of a low dresser (I used to pile t-shirts on top of the board and move them when I wanted to use it). I had a square tub (around 3 feet on a side) in the bathroom and Iwould put a piece of pine (around 12" wide) across the top with my trays set up on it. I would put the wash tray in the bottom of the tub and let the faucet run into it.
Having recently moved into a house, I was trying to figure out how to put a proper darkroom into my laundry room. Reading this made me remember the extra bathroom down in the basement (that I have yet to use). I'm figuring on a table for the enlarger and then an extension to the already sizeable countertop by the sink for wet process.