Big problem with the South Loop Trail.. if you park at the lower lot (outside the park boundary) you will see a sign "S. Loop Trail .3 mi" telling you to go left at the top of the stairs. WARNING, this is the LAST sign you'll see and if you follow your instincts you'll be going up the WRONG trail to Cathedral Rock instead. This is a bad oversight on the part of the park management. We continued on this trail until it dead ended beyond Cathedral Rock. By then we knew we were on the wrong trail but continued anyway going up a very steep (almost dangerous) inclines that had been traversed by only a few people who, undoubtedly, had been misled like us and were determined to get to the top. Route markings were occasional piles of rocks and mild signs of foot traffic. Only the most experienced hikers should attempt going up this way and certainly not come down via this route(!) We lucked out and made the right choices at a few junctions where we had to decide to go left or right when facing a vertical wall of rock. This unmarked path brought us to the top of the ridge between Griffith and Charleston about a half mile west of the junction of the ridge trail and the correct trail up the mountain. The best way to be sure you're on the correct trail is to not enter the South Loop Trail at the lower lot. If you park at the lower lot, walk up through the park gates and take the trail that is clearly marked "S Loop Trail" which is a different entrance than the Cathedral Rock entrance. They are about 100 feet apart. DO NOT get sucked in to entering via the lower lot. You will get lost, just like 3 other hikers did this morning. One turned back when faced with the 40 degree incline, us and two other very experienced European hikers continued straight up. No switchbacks here. Every step had to be calculated.
Thank you. I appreciate the update. I've integrated your comments into the South Loop route page.
According to birdandhike:
the Harris Road path is closed til 2019.
And of course, south loop trail is also closed.