This is a little out of your way, but in Reno, NV there is an old ATT site on
Peavine Mountain [good graded gravel road easily accessible].
I saw the tower listed as "undetermined" in a Bell System map that Albert
LaFrance had posted about a month ago.
I grew up in Reno and moved from there to Denver 10 years ago--before I was
really into cold war comms and such, but on trips to that site in the 80's I
still remembered it as active with a large building--looked to be above ground
and underground--complete with large venting for what appeared to be the exhaust
for a very, very large generator.
Co-located on the site is a transmitter for Channel 4 television [I also used to
work for Channel 4 as a news assignment editor but never thought to talk to any
of the engineers that frequently went up there.]
Anyway, if you get the gambling bug while in SF and just happen to be in Reno,
it's worth a look.
Peavine mountain is about 10 miles north of Reno on Highway 395 and the gravel
road to the top of the mountain is near the Stead exit.
[PS: If you get about 50 miles south of Reno on 395 you could also visit Topaz
Lake site where the building there had washers for cleaning the fallout off of