In the past I've done some work to prepare for a backpacking trip where I did sets of stairs (not stairmaster... actual flights of stairs) with a fully loaded pack on my back for a while in anticipation of the climbing uphill that was coming.
At the time I did about ninety flights up, ninety flights down with a seventy pound pack on (followed by some flat walking for about four miles) and could barely walk for a few days afterwards
How effective would something similar be in building leg strength for cycling?
We have six flights of stairs in the building in which I live... and I hate the gym, so I dropped the membership. How useful a method might that be to get some added leg condition?