http://binged.it/1NQnPTe
Armed with this info, I went over there to check this out, and it's just the quick route I was looking for. The route starts on a pullout-less section of the highway, and the ridge down looks like this:
The ridge route from the highway to the power lines (ridge on the North edge of Twin Canyon) is an old roadbed:
This is overgrown, but mostly with plants of the soft non-poky and non-poisonous variety, so it's easy going. Once at the towers you leave the ridge to the North (away from Twin Canyon). Here is a slightly-overgrown flagged trail with several switchbacks:
Some didn't make it:
This eventually ends up in a steep gully, which has fixed ropes in it to aid in the descent. The gully drops you off at the mouth of Dark Canyon, at Oakwilde:
There I met two hikers who bushwhacked their way from Switzers. They were surprised to find out that the Gabrielino trail doesn't exist in that area, and disappointed to learn that Oakwilde doesn't exist anymore either. Their report of the conditions upstream is that the Gabrielino is in good condition until it drops into the river, at which point it's a heavy bushwhack.
I then walked down to check out the bypass around the Brown Mountain Dam; it has been worked on, and is in great condition. The river is currently dry in that area, and the Oakwilde - Dam section is very easy going.
I got what I wanted, and turned back the way I came at this point. Looking back at the ACH, one could see several long road cuts below the highway. I'm guessing they all connected to the road running down from the CCC ridge, since you can see the cuts pop up periodically at a similar height to each other. A (large) photo showing some of this: https://gal.secretsauce.net/travels/San ... d_cuts.jpg
