For processing film, I have a small box, it fits inside small a "rubbermaid" dishpan and fits on a shelf in my closet. In the box is:
- a 35mm spool and tank
- a 120 spool and tank.
- a 125ml bottle of HC-110 concentrate
- a syringe for measuring the HC-110.
- a small plastic graduated cylinder
- a small plastic funnel
- a thermometer
- a 250ml bottle of stop bath for use with 135
- a 250ml bottle of rapid fixer for use with 135
- 500ml bottles of stop and fixer for use with 120.
- a bottle of photoflo
- an empty HC-110 bottle, that I use for mixing developer just prior to use.
- an empty 500ml plastic water bottle for mixing the photoflo before use.
- a hair tie and some clips for hanging the film afterwards
- some nitrile gloves.
To develop a roll of film, I spool the film in a changing bag, then put the needed items into the dishpan and carry it into the kitchen. When I'm done and everything is washed and dry it all goes back in the box ready for next time. Fix capacity is 6 35mm and 12 120 films. I make fresh fix and stop when I hit those limits. The box is always ready, and if I want to develop a roll of film, I never have to mix anything or go looking for anything. Simple, convenient, and doesn't take up much space.
( I am cheating a little bit: I have space out in my garage where I keep the bottles of stock solutions and other things that I don't need as often. But it's not in the house taking up space.... )
Also I think Parker Smith has a good idea and you can also use single tray processing and then to make prints you just need three wide-mouth ( plastic is better ) bottles: developer, stop and fix. Keep track of how many prints have gone through the fixer and mix fresh when needed. When you wash your print, wash your tray or drum ( or a pitcher with a lid that seals well works great for 5x7 or 8x10 prints ) and you are ready to make your next print. For test strips, you can use a few small glass jars, and then you don't need to wash your tray or container out until you've made a print. Minimal setup: 3 small jars and a container or small tray for the print. Have a "tally sheet" that is in easy reach to keep track of how many prints have gone through the fixer. If you use a 250ml bottle of fixer, you can make fresh stop every time you run through it. If you use a larger bottle of fixer, you will need to refresh your stop bath more often, before the fixer is used up. Once again the idea is that you can go make a print any time that is convenient, with everything ready to go, and not needing a lot of mixing or preparation.
Edit: for FB add HCA or sodium sulfite bath, and a separate tray for washing....
Also: Some trays sold in office stores have lids and the plastic is very hydrophobic, so when you pour out the solutions, there is very little carryover, they are nearly dry after pouring. Some have square corners that pour easily without spilling. I like to use these for my salt prints, which I do entirely with single-tray processing.