The trail you are talking about comes off of HWY 173, not 178. It begins where 173 first becomes dirt right where it begins up into the mountains headed generally east towards Lake Arrowhead. The trail goes from the HWY basically northerly thru a canyon towards the back side of the dam where the spillway is. Then go to the top of the spillway where there is a trail which switchbacks up from there on its north side up to the PCT above the spillway, and then the PCT follows the old Hesperia Aquaduct back a few miles to the bridge and to DCHS about a mile and a half beyond that. The section of the trail from the dam to the bridge has lots and lots of graffiti. I don't even hike that route to the springs any more because of the ugly graffiti. I think you would be better off either taking the Bowen Ranch way in to DCHS or going by way of the Bradford Ridge trail. Both of these route directions can be found at the DCV website link below on this page. Good luck :-)