Gail there is no right or wrong way to set up your media folders/ sub folders–it is all up to what you want…
Some people divide it into to Census/ Marriage/ Birth etc. and some into family units–here is another good post to read…
But I am getting the idea you want to do both-- subfolders for each major family line and then record type under each major family line-- that would work just fine also-- you could even do a separate sub folder for your father’s sister and mother’s brother who married or even sub folders for every sibling in a line…
In my opinion, the hard part would be setting up the folders and getting what media you already have in the right sub folders