I cannot offer any solutions here, which is one of the reasons why I started the topic. I can definitely contribute a history and series of decisions that did NOT work for me.
My situation is far different than loebtmc's. The need for adaptability that was not stressed enough during my education. I never got over the culture shock of going from the big houses that I trained in down to the little piddly companies that I ended with years later. By 2003 the inability to adjust to life without job descriptions ... and the sheer contrast of that life with what I had been trained to expect ... was what led me to leave SM altogether.
In my new job (outside of theatre) I wear four hats, have no direct report, no set hours and no set paycheck, but I am happy because it has been like this all along since the day I was hired. I had no expectations of anything else.
I trained at a college with three dedicated stages plus a student black box, a well-appointed scene shop, at least two assistants on every show. I only had to tape out a set twice in four years. I never needed to pull rehearsal props because we were working with the real things within 2 days of the request appearing on the reports. Every instrument was grounded and every house had permanent catwalks. I was ripped a new one if I either tried to do someone else's job or didn't do exactly every single detail that was included in my job description.
I did do two summers at "stock" theatre. I had been warned that stock was about pushing yourself as far as you could rather than about production values, so I wrote off the quality of the environment figuring that it was atypically poor. I absolutely loathed stock, but figured that it was a rite of passage and things would never be that bad again. It turned out that the rest of my career was in houses far more like the stock environment.
My first gig after college was a year spent interning at a company with even MORE support and established systems than the university had. I was an intern and I was treated like chattel. I accepted that as "paying dues."
By the time I started freelancing in 1999 and had the squishy mat of financial endowment pulled out from under me, I was 22 and had done 25 massive productions in VERY elaborate environments. From that point forward I never again had an effective assistant, I never again had a rehearsal space that even approached the size of the actual stage, and I never again did a show where I was the stage manager and ONLY the stage manager. After four years of trying to adjust I never really did.
In some ways my personal beliefs contributed to this inglorious end. I saw how union contracts affected decision-making in the larger companies and opted not to join. I am not the kind of person who asks for help - if I see a problem, I'll certainly try and fix it but I generally assume that nobody else is interested in trying to fix it along with me. Collaboration is not one of my better skills. I am more competitive than cooperative. I am selfish. All of these traits serve me very well working as a solo real estate agent. They did not blend well with stage management.
While I did draw the line in certain places I probably didn't draw it in the right places. I did quit shows for racial harassment and sexual harassment, but I had no problem doing laundry alone at a laundromat six blocks away (without a car) for casts of 20 without extra pay. I threatened to quit (but didn't) when ASMing for a supervisor who regularly called me a "useless piece of !@$#" and threw props at me, but had no problem doing preset for a 3 story tall set on two sprained ankles. I have numerous physical problems now that trace back to the theatre years and may never heal. I am no longer able to run, jump, dance or climb ladders because of 18 sprains between 1998 and 2003. I cannot sit in the same position for more than 20 minutes at a time because I shattered my tailbone during a load-in while trying to lift and preset a couch alone. Some of you will read this and laugh and call me a baby. Others will be horrified. In retrospect after several years back in the real world I certainly am. I drew the line at the wrong place - perhaps I adapted too far or expected too little by the end?
So yeah, windy as usual. But what you see above should be an abject lesson in how NOT to do it. I don't know what I should have expected, but it wasn't what I got. I don't know how I should have adapted, but I didn't. I don't know if I had the right personality to be a stage manager or if it was just the wrong choice all along.