Mt Laguna is 6,000’ in elevation and is somewhat in the area, probably being to the N/NE of the suspected last known ping location.
EXCERPT:
Early Wednesday morning, there was heavy precipitation in the area where officials received the last ping of the missing helicopter at 5,300 feet, where some snow was accumulating. There is anywhere from 6 to 10 inches of snow accumulation, with even more on the way.
https://www.foxweather.com/weather-news/missing-marines-helicopter-squadron-las-vegas-san-diego
Wouldn’t have been the first aircraft to go down in that area due to a Pacific storm with heavy winds and probable icing conditions. A better route may have been the Banning pass area then WSW to the I-15 corridor to Miramar. Still very dicey for a low flyer in that weather.
The flight should have waited for better weather.