I share your frustration with access. Went scouting yesterday, having hoped to climb from north along a road off Peru Dr between Advanced Refining Concepts (611 Peru Dr) and Gopher Rock. Road starts at 39.551804, -119.514580. There is a gate with a shiny chain and lock, but no sign. Couple hundred feet past the gate there's a sign no-trespassing will-prosecute.
There was a sheriff's car parked at A.R.C. so I stopped and spoke with the friendly officer. He told me that this is all BLM land (south of where we were on Peru Dr) and I was welcome to step off the road and start walking.
This morning I looked at the Tahoe Reno Industrial Center website, they have quite a few maps. Some have a quite expansive view of their property, including, as you've noted, the peak of Clark Mtn itself. Other maps show lots and parcels only adjacent to the roads.
Couple other things puzzled me. (1) Many of the signs mention high-speed vehicles. Really? The signs also mentioned "Wide Open Reno" with a Reno phone number. Web search today show a Baja style off-road motoring event, but no sign of any such activity in the last 3-4 years. (2) I was surprised to see that the road going up into the hills is strung with overhead power lines.
I took some photos, hope to post in a few days.