Also a big fan of this loop. My variation which makes it closer to a true loop is to go up the SE ridge from the Wilson trail to Jones. It is steeper and brushier but much more direct, just the way I like it.
I've done this loop (except that I got on Yale's ridge at a different point off the toll road than described) and a variation starting at Bailey Canyon Trailhead. Generally, I go all the way to Mt. Wilson after Yale.
Hiked the Mount Wilson Trail from Sierra Madre to Jones Peak and via Hastings Peak to Mount Yale. On the return I took the Mount Wilson Toll Road to the intersection with the Mount Wilson Trail and down the Little Santa Anita Canyon to the trailhead. In total about 16 miles and 5,100 feet elevation gain. Great day hike with beautiful views and a rarely visited peak (Mount Yale).
"After the first glass, you see things as you wish they were. After the second, you see things as they are not. Finally, you see things as they really are, which is the most horrible thing in the world."
--Oscar Wilde on Absinthe