"...There is no trail and we had no knowledge of other people having done it. We had no idea what to expect. Is it possible to descend Haddock Mountain into the Potrero John Creek watershed and make it to Sespe Creek with a only a pair of boots and trekking poles, no ropes, harnesses or other such mountaineering gear?..."
note: heard of Google? Ok, end of rant since there is too much to say here.
"....And we made mention of it; how smoothly the day was playing out.
Then within probably like fifty yards or less after resuming our hike, as if the mountain was mocking us in response to our discussion a few minutes before, we came across the first real obstacle. It was precisely what I had been concerned about; a substantial waterfall impossible to descend and with no apparent route around it upon first glance. This sucker was tall and hemmed in by steep rocky cliffs and crags on either side. And at this point we were deep into our hike. Returning back to the top of the peak would have been ass-kickingly miserable! We had to locate a route by which to continue down canyon....
Leaving the slope of loose rocks we penetrated through a section of heavy brush, our only bushwhacking of the day, and popped out atop a ridgeline overlooking a huge section of scree.....We slid slowly down it on our butts digging our heals into what little loose rock existed and in some places skidding the soles of our boots on bare rock, while bracing against out trekking poles, and trying as best we could to not break into an unstoppable free slide...I was a little more squarely line up to the tree, and as I came sliding toward it a bit faster than planned, I was able to stop myself by jamming my foot straight against the trunk. From that point we were able to walk-slide down the remainder of the slope which had a far deeper coverage of gravel....

We made our way down numerous unnamed good-sized, respectable waterfalls or cascades before arriving at the largest one, Potrero John Falls. Potrero John Falls was the last obstacle to get around and once we were there I finally breathed a sigh of relief; there was no longer any question that we had made it down the canyon...."