Hi all! Shannon and I hiked the Gabrielino Trail Jan 17-18 and took some notes on the conditions, detailed below.

Note: The tracks on CalTopo say it’s about 27 miles from Chantry Flats to the JPL East Gate - Tracking this hike on my Garmin totaled about 30 miles (subtracting a few spurs we took).
5.2 miles | +2400 ft / -430 ft

This section is popular with day hikers and generally consists of well-traveled and well-maintained trail
2.75 miles | +0 ft / -1030 ft

For the most part, the trail on this section is impassible. A little bushwacking from Newcomb Pass gets you to the Ricon Truck Trail (a fire road), which is a gentle downhill grade all the way to the West Fork Trail Camp.