I live in SF and work in RWC. Either place is good. Beach chalet is going to be crowded or the weather will be foggy (or both). Generally the Beach chalet is PACKED no matter what.
An alternate to the parking lot at the beach is to cruise into GGpark, it's right behind the Chalet and there are areas that can be reserved....Chrissy field is totally redone and VERY cool but there may be space issues and the cafe is rather small.

God...I better get my Empeg installed before the meet, wait...I need a tuner (stupid single DIN M3)...FOR THE LOVE OF GOD, SOMEONE MAKE A TUNER FOR THE EMPEG ;0)