I remember the first night of ground school, I started in the middle of it, the instructor said 95% of general aviation accidents are pilot error, I didn't believe him them and found out as I became a pilot later he was correct
I had sold 2 of my drag cars at the end of 1988 and had the money and time to learn to fly so I started right away after taking a 45 minute demonstration flight at the local training facility in Apple Valley, CA
I've flown over that crash site years ago in a friends airplane flying to Santa Barbara airport to pick up his two daughter who had spent the weekend their with a friend of there family, that is a very hilly region between the coast and the San Gabriel Mountain and the end of the Sierra Mountain range to the east in Antelope Valley. The Hollywood hills are to the south of that valley also so radio contact with L.A. Approach, the air traffic center for that area, is no good below the hill and mountain tops, we found that out the hard way on that trip
I don't remember the MEA, minimum enroute altitude, for that area but I would bet money it is above 4000 FT. above sea level.
Helicopters may have a special flight path through that valley from the San Fernando Valley west towards Santa Barbara and the Ventura areas with a lower MEA, maybe not