That looks like a female Diapheromera femorata. Beautiful brown color! They're usually green. She may be moulting soon. Here's a caresheet for them.
Nice find! I've only seen one in the wild and I've lived in Ca my entire life.
I would really like to find one of the Timema species. I've been looking when I go hiking but I think they're kind of rare in my area.
I wonder what kind of stick you found if it's not a Diapheromera. I guess there are quite a few species of sticks here in California.