This is a close ride starting at JPL.
Lower Brown Mountain Fireroad - An uncovered fireroad climb. It is
about 6.5 miles to the end of the climb. The fireroad actually doesn't go
anyway.
El Prieto Trail - This trail starts about 1.5 miles from the
lower/upper brown mountain saddle on the upper brown mountain fireroad
side. This is a super fun, somewhat technical descent. As you descend, you
have several options along the way to take the high or low route. The trail
is about 2.2 miles long and will dump out where the lower brown mountain
fireroad just begins its ascent.
Ken Burton Tral - This trail begins at the end of the lower brown
mountain fireroad climb. It is a fun and fast descent down to the
Gabrielino trail. Along the way, there are over 20 switchbacks to navigate.
I find I can only clear 50-70% of them. Some are just too hard for me to do.
The trail is about 2.5 miles long and ends at the Oakwilde camp along
the Gabrielino. The trails doesn't get much use beyond the MTBing community,
I think. It is just too far away and doesn't really go anywhere for hikers to
use. As a result, the trail gets overgrown easily.
Gabrielino Trail - The Gabrielino trail that begins in Chantry Flats
and winds it way through the San Gabriel Mountains, ends here. Along the
way there are what seem like an infinite number of stream crossings. Some
are ridable, some require me to hike-a-bike. But it is a very
nice ride as being in the canyon between Switzer's and JPL gives a certain
remote feeling, only to be taken away with the passing car whizzing by
on the Angeles Crest Highway above.