My weekend-walk decision-making system used to be: keep walking south. I walked south until I was tired, then caught transit back home. The next time I wanted a walk, I rode transit to the place I'd stopped previously and walked south from there until I got tired; which became the starting point for the next time.
This was a fine, simple system, but hit a snag. I didn't especially want to spend four hours riding transit to support a 1.5-hour walk. Or devoting half a day to a little walk that was supposed to be simple.
I started over: the next time I wanted to walk South I didn't go to last-walk's stopping point. Instead, I rode the streetcar out to Ocean Beach and walked south from there. For my next few walks, I kept walking south, but now a few miles West from my previous set of walks.
But I once again found myself spending too much time on transit.