Your approach (“taking notes on the people he cites, both in his books and in his video interviews and lectures”) is exactly what Joseph Campbell recommended: instead of reading works that are said to be important, or are on the nonfiction bestseller list that year, find an author who speaks to you, read everything you can of his (or her) work, then pay attention to his influences, the writers he cites, read their works, and then who they read and so on – and sooner or later you will end up with a comprehensive worldview.
Though he did earn a Masters Degree, Campbell was primarily an autodidact – most of his erudite intellectual expertise developed out of those five years reading books during the Depression in Woodstock. I have had the opportunity to spend time with archival materials from JCF’s files: Joe would make copious, detailed outlines, often comprising a relatively thick sheaf of pages, of everyone from Oswald Spengler to Stanislav Grof.
As for his assigned reading list, Joe would often tell the story of how one day his students complained that they had other classes too, and just could not manage to read all those books in a single year. His response? “I’m surprised you even tried. You have the rest of your life to do the reading.”
I envy all the reading you have ahead of you. Enjoy!