This is not a question about a particular period in history -- it appears to be about modern Japan -- so would be better asked in a subreddit about Japanese culture.

(Just based on the documentaries I've seen, the question lays out a false dichotomy. A person can visit a monastery and enter certain areas as a guest, but could not go everywhere. Similarly, there are plenty of books laying out the various rites and routines that monks go through, but there's nothing requiring a farmer to know them.)