> Twenty-two miles across the San Gabriel Mountains,
> however, the site of the mirror that bounced the
> light back to Michelson is impassable to even the
> most-determined hiker.
I am REALLY surprised to read that sentence.
I walked up Lookout Mountain (6,812') and Sunset Peak (5,796') in mid-1997 and it was closer to bare than it was to overgrown (and both mountains took just a few hours to visit from the parking lot).
While there was a short steep bit towards the top, it was not overgrown, and didn't seem like a difficult or epic hike at all.
I suppose that 5+ years of no trail maintainence could explain the overgrowth, but it was not "impassable to even the most-determined hiker
", in fact I considered it very easy at the time (things may have changed since I hiked it)...
These mountains appear on the "Hundred Peaks Section Peak List
" of the Sierra Club in LA, where they rate it as "Class 1, Moderate" and suggest 4-4.5 hours for the roundtrip of 4 miles and 2,300' of gain (they also mention a bit of bush to contend with).
The foundation of the place where the experiment was held is still there.