Okay, there are benchmarks on the ground from when John Ware had the area surveyed in the late 1970's. These are USGS benchmarks done by the U. S. Geological Survey.
These benchmarks are round about the round size of a coffee mug, are 2" brass caps which have numbers and identifying marks, are on a 2" pipe to anchor these to the ground to make these permanent, and usually have rocks around them for protection from the elements.
The first benchmark to look for is pretty easy, when you are on JF-4 and curving by the ranch where the road is heading west past the Bowen Ranch where the road turns to the north, the benchmark is not far off the road to the east. Estimated as extremely close to the road toward the Bowen Ranch.
The second benchmark is located after you drive south from the Bowen Ranch toward the Rancho Las Flores parking lot. Anyway as the road does a sharp turn to the west, another sharp turn south, you have cross the boundary to the Rancho Las Flores Land. It is steep, rough and rocky right at the turn. The easiest route to find. You park at the parking lot, you walk on the road like you were going to the former lower parking lot, you walk down the hill until you are in a wash/gully look north, turn walk northly about 200-300 feet, when you can visually see where the sharp turn in the road was to the west, you are about in the right location. The benchmark is not directly in the wash, it would be on the side of the gully on the east side.
So, if you are interested, these benchmarks can be located. Survey was already done.