I sense that this is likely not what the OP is after, who seems to be seeking a more elaborate and searchable system, but mine couldn't be much more simple and straightforward.
The path to an individual RAW image would be
Pictures/yyyy/yyyy-mm-dd/IMGPxxxx.DNG
and that's basically it. Surely, from the time I was using Lightroom I had a catalogue, but I found that I never bothered to tag images and instead relied on my memory of the year and the rough month an image had been taken.
I do create topic- or occasion-named export folders for my processed JPEGs and upload the keepers to similarly-named galleries on my SmugMug website, which also effectively acts like an informal "index" that makes it easier to locate individual images.
Sometimes, it will take me a moment to find a specific image, but this has never been a serious issue as I don't have to work for clients, and the "lean approach" has made me independent from RAW converters with cataloguing functions, which would consume considerable hard drive space that I would rather use for images.