When the cave in occurred it just opened up 10 to 15 feet of the tunnel behind the portal and produced only a few cracks in the pavement of Pinehurst Rd above, and many feet behind the portal. The portal was only covered over in the resulting cave in repair job.

Go to google maps at this link and select the "Street View" option. Is this the "12 foot guardrail" on the lower stretch of Pinehurst? If you select the upper section of Pinehurst, you can see the "double guardrail". Link: http://maps.google.com/maps?f=q&hl=en&geocode=&q=moraga,+ca&ie=UTF8&ll=37.840462,-122.182944&spn=0.001396,0.00339&t=h&z=19&layer=c&cbll=37.84004,-122.183013&panoid=VfuzeY3zN4u8_8qyYi9DKA&cbp=1,175.08999999999978,,0,5

Hey yeah that's it exactly! You can see the small path going up.

My buddy and I went down there from the Moraga Side. We saw the right of way while coming down Canyon Rd. The entire right of way is still there throughout canyon, tough to find in some spots but we trekked through there all the way to the tunnel (or where it was) and it was obvious that something was there at some point because of how flat it was and how massive the flat hillside was. Unfortunately we were being mugged by the local residence of Canyon so we decided to jet out of there. It was surreal to finally be there.