I walked the entire Baron Ranch Trail this morning, including the upper loop. Not sure how long that is but it's 2.5 miles from the parking spot to the beginning of the upper loop, which seemed to go on forever. I would guess I walked a total of 7.5-8 miles.
The upper loop trail is badly overgrown with weeds and grasses so it's a slow hike though not otherwise terribly difficult. Eventually it meets the head of the canyon and the riparian area at this point was interesting, but I didn't see anything different from what I saw further down.* There were lots of Purple Finches at this point. *The one exception was an apparent young male Costa's hummingbird in the Chaparral portion.
There was plenty of bird activity along the main trail and creek, including lots of singing Black-headed Grosbeaks. At one point above the ranch headquarters I had a singing Robin as well, which made for a nice comparison between the two species' songs. I had singing Yellow Warblers all the way up the creek, including at the top of the loop, and at least 6 Canyon Wrens sounded off.
The stars were the Phainopeplas. In the riparian area bordered by an unkempt orchard I began to pick them up and had at least 6 before I got to the loop trail. On the first part of the loop trail, I had 6 more, and then picked up two more on the way down near the end of the loop.
I am extremely grateful to those who posted info about this trail, as it's well worth the hike. I also thank the owners for making this trail available Sat-Monday. I plan to hike it again in the fall, and also earlier in the season next spring.