Marc J. Zeitlin wrote:

I'd recommend NOT going through the Cajon/Banning passes, but going
around Big Bear to the north and east, and then cutting south to Palm
Springs. You'll still get bumped a bit, but it'll be less than going
through the passes - especially Banning.

I'd agree with this suggestion for a smoother flight -- but be vigilant
near Adelanto for UAV activity. last year I attended a safety
seminar at the San Diego FSDO presented by an Edwards AFB test pilot
who pointed out the hazards in and around the R2508 complex. Adelanto
was mentioned for the high conentration of UAV activity with a strong
suggestion to keep your eyes outside the cockpit when you are in the
area. The footprint for their activty was significant.

Steve