The Old Road is the former US 99 in Southern CA. I headed north through Stevenson Ranch and Valencia, past Magic Mtn and wound up in Castaic. Still plenty of daylight left so I headed up the Ridge Route to a 4-way intersection that gave me two directions to go (the others were not "through" roads). I opted to keep going. Wound up on the old Golden State Hwy headed towards Pyramid Lake. That road also ends. Wish I would have known that ahead of time.
Of course had I planned the trip and checked the route ahead of time I may have gone further. All in all, very scenic. The route is in Google Street View.