It's Farnsworth Park.
I don't know why my brain pulls up Barnsdall, I've never been there but even when I was scouting this place a few months ago I was looking for Barnsdall and meaning Farnsworth.
http://www.lacountyparks.org/Parkinf...tle=Farnsworth
I liked it, but it is about 30 minutes from Alhambra with no traffic.