Tubes can be made from 4" ABS plumbing drain pipe, with glued on plumbing end caps. Some use this material for tanks for reels, or to develop sheet film.
I would scour an established photo store that sells used darkroom gear. They likely have more daylight tubes used than they know what to do with.
Processing RA-4 at room temerature, in trays (with tongs or gloves) is quite viable for most, but could be a challenge in a shared darkroom. It needs total of very dim near total darkness.
For RA-4 I find the safelight is only useful for orienting me in the room. It is almost 20 minutes before I can 'see' anything of use with it, and then only just barely. I find luminescent glow tape placed on the corners of cabinets, work benches, etc and total darkness otherwise is more useful. That, and a very tidy darkroom as well.