You may want to peruse the old Popular Mechanics posting on Google Books. There was almost alway a DIY photo gear article every issue or two mid 50's to mid 60's.
I know I read one that had plans on building a plywood fold up affair that put an enlarging desk at an convenient height over half of a tub; the second half was the wet side, coated with fibreglass. There was a basket that sat under the counter in the tub to wash prints using the tub filler as a water sourcem, and it overflowed to drain down the tub drain. The work table with hinging legs hung vertically on a bracket behind the bathroom door when not in use. I based my first darkroom effort on that article. After that I moved on to a microwave cart for impromtu efforts.
I am pleased to hear of the fun you are having with good old film stuff.