Much about this seems implausible. Classes are in the morning, not work. No applicant would be left alone to work - why? It's rare to have en-banc candidate interviews, and then only with the ~10-member applications committee. Also, the posting is 15 years out of date; after 7 student-generations, it can say little about Deep Springs today. But possibly it was true.
Deep Springs gives the 24 2-year students all the responsibility: to pick faculty and students, to actually run the ranch, and to govern themselves.
Part of that is ensuring each generation of students decides for themselves: practices survive only if the current generation adopts them.
Another part is that people commit to taking you seriously; i.e., you will be held responsible for your bullshit (er: taken at your word), e.g., "the people who read this essay at the school thought my idea was groundbreaking" means "The most interesting thing was this essay, so they went with it."
Another part is the "isolation" policy: students don't leave during term, and more generally avoid outside influences (the internet has been a big issue, obviously). The goal is for you, together only with the people you have with you, to take full responsibility, and gain full authority, using what you have at hand.
As a consequence, outside interest is Deep Springs, while necessary for the validation to recruit good students, is mostly discouraged -- to avoid influencing how the current students decide how to run things, and certainly to avoid visitors or internet conflagrations.
It's extremely rare for students to have this combination of freedom and responsibility and feedback. It should be replicated. It's almost always life-changing. So if you know any brilliant, caring, and productive people about to start college, please ask them to consider Deep Springs.
Otherwise, please forget about it :)