Up the Arroyo Seco at the Paul Little Picnic Area there used to be a trail that went on up toward Inspiration point. I’ve been up looking for it a few times and today I found it.
It starts up the east canyon wall about 4 miles above the JPL parking lot. I followed it for about a half mile before I ran out of time. But it looks like a promising way to make another Pasadena loop hike. Why it is closed is not yet clear.
If asked why you are on a trail that is closed answer that you are not on the trail you are bushwhacking. Bushwhacking is still legal but going on a closed trail might be illegal.