My current 'darkroom' is nothing more than a tiny bathroom. My enlarger sits on a small rolling cart which I wheel into the bathroom. I sit on the toilet and can print pretty comfortably.. My trays sit in the tub, easy to clean up afterwards.
Hardest part is setting up everything. I was spoiled, having a dedicated darkroom with a wet room and a dry room. Ah well. I miss having a 'real' enlarger. I'm using an Omega C760 (flimsy) but used to use an Omega DII (workhorse)..