It was 6p before I reached the main gate with the dirt road heading west into the ranch areas. There were two large trailers parked just off the road at the gate, with taillights and running lights ablaze. I mistook these initially for large cattle or horse trailers and figured they might just be coming out of the ranch, so I passed them by and parked about a quarter mile further south along the road where I knew a spur road could get me back to the main dirt road leading west. The trailers turned out to be people trailers, the type used for mobile film crews, I found upon exiting. They were still there with a few running lights still on. Perhaps they are filming a commercial for a car or something in the area.
I had hopped the fence and hiked in about a mile when I spotted headlights
coming from the ranch area. I had more than enough time to walk over to the
ditch that is Little Panoche Creek and hide there out of view when the truck
came rumbling by a minute later. That would be the only vehicle I would see on
the property. The dirt road is 
wide open to view,
but that worked in my favor
as I would be able to see any vehicle from a far distance, giving me plenty of
time to get out of the way.
The moon had risen about an hour earlier and would easily light the landscape all night without a need for the headlamp other than to check my map. The roads depicted on the topo and GPS only partially matched what was really there, but the main roads were both accurate and sufficient. I found half a dozen herds of cattle in Little Panoche Valley ranging from 10 to 50 head in size. Some of them were curious to see if I had some good eats to offer, but all eventually turned and ran upon my approach. There has been no rain to speak of in almost a month and the ground is very dry. The cattle have eaten most of the dry, brown grass making cross-country travel very easy. I left the main road when I discovered this, making a more or less beeline for Ortigalita which I could see to the right of a long ridgeline ahead of me to the west at the end of the valley. It wasn't the best route in hindsight, as it took me in and out of several small drainages on my way across the the valley. The road has no such elevation changes as I found on the way back. As I passed to the north of the ranch buildings I saw no lights, suggesting it is not permanently occupied.
I followed the Southeast Ridge directly up to Ortigalita's summit. Though quite
steep, there were ample cattle trails along the route to make it easier. The
ridge rises nearly 2,000ft in about a mile, by far the hardest section of the
entire hike. It was just after 8p when I reached the top where a small
summit cairn held erect an old wooden stake. There was no register,
but I did find 
a benchmark.
Dropping down the northwest side, I soon picked up the ridgeline
road that I had identified from the satellite views that would take me the
remaining distance to Bonanza BM. The road was actually a series of connecting
roads that stretched over three or four
property boundaries. The initial section
was in good condition and had tire tracks indicating recent use, but most of
the roads were old and no longer used for vehicle travel. Luckily there were in
fine condition for cattle and nighttime human visitors.
I jogged most of the downhill sections going out and back to Bonanza BM, taking perhaps an hour off the time it would have taken if I just walked the entire evening. The views off the ridgeline were quite fine even for night. The lights of Los Banos, Mendota and smaller communities could be seen to the north and east, while much of the darker interior of the Diablo Range were seen in other directions. The moon was so bright that even without the aid of lights, the Diablo landscape was clearly visible in excellent detail.
I arrived at the Bonanza summit by 9:15p. There was
a huge cairn over six feet
tall found at the summit. An examination found that it had been carefully
constructed and quite solid. I was able to climb halfway up without disturbing
a single stone, but declined to stand atop the uppermost rock lest I might fall
and break my leg. I was unable to find the benchmark anywhere at the rounded
summit despite a most thorough search. Possibly the cairn had been built atop
it. I didn't find a register in the cairn, though that search was less
thorough - I figure is someone is going to make it difficult to find, then I
don't really need to find it. I took some long exposures with the camera,
north to Los Banos, 
east to Mendota, and then 
west
towards the range interior. These
came out much better than my previous attempts, thanks in large part to the
absence of any wind to speak of.
I returned to the northwest side of Ortigalita via the same route, then used a dirt road that traversed around the north side below the summit, saving me the need to reclimb to the top. Where the road ends or turns north (the topo map shows it heading north, but I didn't really see this - it seems to end at the saddle NE of the summit), I followed a fenceline down to the next ridge east of Ortigalita and followed this back down to Little Panoche Valley. The descent route was much more efficient and saved much time. The only difficulty was avoiding a twist or turn of the ankles as I jogged down the hillsides littered in places with loose rocks.
Once back on the flatlands of the valley, I took the road to the
ranch buildings
where I found nothing to disturb the evening's quiet. There were
plenty of old, rusting ranch vehicles and trailers that looked to have last
been used thirty years before. An RV at the south end of the lot looks like
the temporary quarters when folks are working the ranch, but all was quiet
tonight. On the way out of the ranch, I found
coyote carcasses hung from the
fenceline that borders the road I followed. I counted 37 of these grisly
displays in about half a mile. Evidently the rancher or ranchers have an issue
with coyotes and have hung them to discourage others or perhaps in way of a
trophy display. They were mostly quite old and decayed, with varying amounts of
fur still clinging to the desicated bones, all the soft tissue long gone.
Probably a good thing I didn't encounter anyone on this evening.
It was midnight before I returned to my car. The last hour across Panoche Valley had been pretty cold and I put on the fleece I had taken off earlier when I was first climbing to Ortigalita. It would be 2a before I had driven home, taken a shower and gotten to bed. A most excellent hike, to be sure.
Turns out Bonanza BM is also a CC-listed peak as Ortigalita, I discovered a few months later. In my initial search for a peak named "Bonanza" from the original CC list I came up empty, but it turns out the name refered to the benchmark which I "discovered" from the prominence list. Got lucky on this one...