I did exactly this, print 645 and 6x6 in a tiny bathroom. I used a cart that had drawers and wheels on the bottom and would wheel it into the bathroom w/ the enlarger on top when I wanted to print. I'd sit on the toilet, print and then develop the prints in the tub w/ trays inside. It worked well. No windows to to darken for me. I used a towel at the bottom of the door to block out light and gaffers tape to block light around the door. I left the tape on between sessions.
As far as an enlarger goes, I used an omega b-700. It's great for 35mm but skip it for 6x6. A Durst F-30 or even a Durst 606 (sweet!) would be a great and very affordable choice. I've been wanting a 606 for just this reason..
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.
knee pads---- I develop in the tub, leaning over the edge....hard on the knees.
"I have 4 containers: 1 for developer, 1 for stop bath,
1 for fixer and 1 for Fuji Quickwash (optional)."
One is enough. After loading the tank add a correct
amount of one of several excellent one-shot developers
to the correct amount of water. Stir, pour into tank then
begin agitation. Allow two minutes twixt your series of
Time twixt periods of agitation is used to quick rinse
the container and dissolve or stir in a correct amount of
fixer into a correct amount of water. Fixer can be used
in the same manor as developer, very dilute one-shot.
No stop bath is needed because developer build up
in a one-shot fixer is nill.
While the fixer is at work quick rinse the container then
stir a correct amount of PhotoFlo into a correct amount
"A squeegee for wiping off excess water from negatives"
I use a squeegee. Years ago it was a sponge type but
have switched to an eight blade film squeegee. They are
sold under several brand names and not cheap; $15?
I too have little counter space. I don't mind the few
extra minutes it takes to process using very dilute
developers and fixers. There is a savings in time
when cleaning-up as some can be done in
conjunction with processing. Dan
Another thing I've done recently is to set up a 5x7" tank line in a box--three tanks Acufine (any replenishable developer will work)/rinse/fix--all in a plastic covered storage box to reduce oxidation, keep the odor in, and store it in the closet when not in use. I often use other developers and other methods, but this is always at the ready for quick shots when I don't need pyro, and if I do need pyro, I just mix it in another tank.
Yikes, this is a wealth of information. I just read through it all, though rather briefly.
I'm in the middle of exams, so I apologize for not being able to respond to each post.
Thanks for all of the help so far. I really do appreciate it!