Yes, Mojave, that vehicle does fit the description of the one observed hill-climbing on private property, although it could just be a coincidence. As for the vehicle that vandalized the Village entrance, that may have been a gray pickup. A gray pickup with a flat tire was seen just north of the Village entrance on the same day as the vandalism, but by the time the vandalism was discovered the pickup was gone. The tire tracks matched, and the occupants appeared hung over.
Agreed that Dead Man's curve needs signage. Maybe FOJF can help with alerting the authorities about this hazard.