I just watched the the CA HSR videos and all I can say is, WOW!!
I wouldn’t have envisioned the SR-152 route from Merced (over Pacheco Pass/Reservoir and alongside the San Luis Reservoir) to Gilroy, cuz it seemed too complicated to do. But I see where the inner part of the peninsula (just west of I-280 along the bayfront) is used as tracks thru the Silicon Valley. This seems totally doable.
Luv it.
Just incredible. Hope I live long enough to ride it all . . . regularly, lol!