The IFC was on San Pedro Ridge, north of San Rafael.
The site is now "Harry A. Barbier Memorial Park".
Four concrete pads remain, plus some clearings where the barracks were.
Access: there are numerous mountain bike trails in San Pedro Mountain
Park that head up the ridge.
Or you can walk/bike up Sunny Oaks Drive and Bayhills Drive from the
north side, which is the original Nike road.
There's a gate close to the bottom of Bayhills, so no driving up.
Or, find Gold Hill Grade behind the Dominican College in San Rafael and
walk/bike up the dirt road from there.
Any way you go, it's a thousand foot climb.