If your flight arrives at 4pm, you would be in the height of rush hour trying to get out of LA. Pick up your car, get a hotel room near the airport, go to bed early, and hit the road before dawn to get out of the city before rush hour. Best way to DV is I-405 to I-5 to CA-14. The 405 is famous for its terrible traffic so I'd say that 4am would be a good target time to get going.

You can either stay on CA-14 to US-395 to CA-190 to get into DV, or go into Ridgecrest on CA-178 and take the Trona-Wildrose Road in, which will take you to CA-190 at Panamint Springs.