Even Thoreau didn't live as a hermit - Walden was very much a break from everyday life for him. So I think like all such material the value is helping us to try and live before we die. Because one thing you can say about a less mediated life is that it's more fulfilling and more satisfying.
This was the aim of Thoreau, Gandhi and of course the Buddha - to live life directly without any mediation between oneself and reality. And to greater or lesser degrees they all achieved that.
All these viewpoints, Situationism, Marxism etc. can be dogma or just little clues to help us live a more fulfilling and satisfying life.
These questions have been the main source of my frustration. The closest lifestyle I've encountered that jibes with these ideas is punk. Even then, taking on the identity of "punk" is like putting on a funny mask over your original mask and yelling, "Look everyone, it's really me!"
To speak with Debord: Punk has been subsumed within spectacular society.
Interestingly, Debord seemed to have proposed a life style of Derive, aimless wandering, following one's desires. To me, this resembles the mind set that he tries to attack. Both tell individuals "You are a snowflake! Follow your inner desires!"
Maybe the more during counter life style against the fads and suppressions of the spectacle society, is a devotion to objectivity and naked facts.
Have you read up on Moxie Marlinspike stuff? He's an anarchist, sailer, security researcher, runs WhisperSystems & etc(there's also a documentary he did on getting an old boat, fixing it, and go sailing with his friends). To me that's what a non-alienated life looks like, you do stuff you want and love(my main issue with working for others is that it kills my enjoinment of programming!).
I think the issue is not about "what lifestyle", thinking is lifestyle terms seems to be a byproduct of living in the spectacle society itself! To me this stuff is first and foremost about truth in life, true freedom, but of course this path is arduous, there are uncountable layers of overly-simplified semi-truths over us.
The most radical lifestyle I believe is one in which we choose to actually live, that is to make our own decisions based on an unmediated direct relationship with our own life. Not to follow other people's direction (especially me) but instead to investigate and to try to understand to the best of our abilities how best to lead our life.
It's no co-incidence that both Thoreau and Gandhi referred to the way they lived their life as experiments. Not beholden to some mediated truth but intent on direct living and experiencing reality for themselves.
Punk was invented by Malcolm McLaren to sell Vivienne Westwood's clothes. Punk had it's time, I suspect that the people that bought into this identity would have been just as likely to be 'football casuals' if they had been born a decade later or be sporting 'hipster beards' had they been born two decades later. So yes, just a mask to put on.