Back in the mid-sixties I lived in a trailer for a year or so. Even in that tiny bathroom I was able to set up a fairly functional darkroom.
For film developing, a daylight tank and a changing bag are the way to go.
For printing, you will need a compact enlarger that you can pick up and stash in the closet. The small Beselers (e.g. Printmaker 67) are good, but I'm sure there are others as well. The enlarger sat on the toilet seat in my setup. You need four trays - three for the processing chemicals and one to hold prints pending the final wash. You can put the trays in the bathtub, but that is hard on your back. Try to find a sheet of fiberboard or plywood that will fit over the bathtub to hold them. You will also need a safelight and some empty pop bottles to store chemicals. An enlarging timer is a very useful accessory that will be high on your want list. You will need to figure out an effective way to wash and dry prints. For this setup, it is probably best to use RC paper. You can wash it in a tray using multiple rinses, rather than a continuous flow of water, and you can hang it up by a corner to dry.
You can actually do quality work with a setup like this.