Sepulveda basin at the 405 and 101 is one of the best sites around. there are 3 clubs there, it a free public site so you'll get everything, there are giant scale jets CL and lots of newbies. As for souring, there are a few but not familiar with them
[link=http://maps.google.com/?ie=UTF8&ll=34.173678,-118.480768&spn=0.039482,0.0739&z=14]The basin[/link]