Winter Creek Loop is ~5.5 miles (GPX track shows ~4.75 but canopy can obscure the view of the sky). Trail is largely packed dirt/decomposed rock with sections of exposed rock that may require dismounting. The route has significant shade - particularly once you reach Hoegee's Camp which make the route a good option when other routes (Brown Mtn) are unbearable. Lots of hikers use the area so please follow proper etiquette and yield as appropriate.
Parking is a challenge on weekends. Get there early and have your Adventure Pass or be prepared to park 1/4+ miles down the hill. Cell coverage is VERY limited. There are call boxes in the canyon (Hoegee's and Lower Winter Creek section) that allow calls out to the Adam's Pack Stn. in an emergency. Ride within your abilities and exercise caution. Rescues from this area can be complicated and are not quick.
Enjoyable singletrack clockwise loop with several narrow areas with significant exposure. Starting at the Chantry Flat parking area ascend the paved San Olene fire road above the picnic area until you reach the Upper Winter Creek Trail
trailhead on your right. Jump onto the singletrack here and follow the trail as it contours along the mountain side gradually climbing up the canyon before descending toward Hoegee's Camp. The trail is largely under the tree canopy at this point and becomes more technical with lots of buried rocks and other obstacles.
You'll pass a trail junction to Mt. Wilson on your left. Stay on the main trail and you'll find yourself in the canyon bottom with periodic stream crossings (may be dry). Pass the Mt. Zion Trail
junction sign on your left. Stay right and descend through Hoegee's Camp along the Lower Winter Creek Trail
drainage continuing to make periodic stream crossings and switchback descents around the various check dams in the canyon. Along the way, you'll pass a large number of vacation cabins only accessible by trail. The Lower Winter Creek Trail
exits at Robert's Camp where you cross the stream and ascend the paved fire road (2N40) up the aptly nicknamed Cardiac Hill back to Chantry Flat.
This is a great ride with a variety of technical challenges most of which can be ridden depending on skill level. Several areas may require HAB. There is significant exposure in several areas. Significant portions of the ride are shaded although the ride up Cardiac Hill can be scorching. The area is heavily traveled by hikers on the weekend and proper trail etiquette is mandatory. Stop in at the Adam's Pack Station for a cold drink and food. They sometimes feature live music on the weekends. Come early to beat the crowds and find parking!
Many of the cabins in the canyon date back to the 20s and are only accessible via trail. The Adam's Pack Station is one of last pack stations in CA using mules/donkeys to ferry supplies to the cabins in Big Santa Anita Canyon. Many of the locations are named after vacation camps that existed during the Great Hiking Era in the San Gabriel's before the Great Depression and WWI.