After reviewing the videos, a few thoughts...
If driving during daylight, the driver may have been distracted by looking at the scenery and not on the road. According to the newscast, it was their first time there. They stayed at the Reedley Inn asking how far it was to the park.
If this video is recent, I noticed some tire tracks (:26) in the dirt. Judging from the tracks in the dirt, the vehicle may have left the road at a high rate of speed and the driver lost control in the gravel. I noticed no skid marks on the asphalt and no braking marks in the dirt. They impacted the guardrail at head on and became airborne at a high rate of speed.
Had they hit the rocks to the right, they could have possibly survived the impact and rested along the road.
Also, if during the day, where was the sun at the time of the accident? Did it blind the driver when they came around the curve? If they we headed westbound out of the park this may have contributed to the accident.
I also noticed in the video there was not a traffic sign alerting drivers of an approaching curve to the left.
CalTrans will need to extend the guardrail out into the turnout and post a warning sign of an approaching curve and the speed limit to negotiate it safely.
Just my thoughts...
Have fun and enjoy the Gr8 Yd Opn.