Over Grapevine, southbound I am usually at 7500' with plenty of comfort in the pass, 8500' northbound. You may loose radio contact for a while over Gorman through the pass when you get handed off to LA Center.
Over SBA, I fly at 3500' down the coastline if I have newbies and wanna add in some sight seeing (although your emegency landing options are limited in areas), 5500' feet if I wanna enjoy the scenery, 7500' or 9500' if I just wanna get there.
I plan for the SRFA as the backup going into Orange County area...there is not ATC communication required other than CTAF radio position calls, so there is no denial into Bravo and is easier than trying to navigate around and under the Bravo if you are unfamiliar with it. For the locals, it is probably every day flying.
In Foreflight, I have ALL the routes through LAX mapped out from the entry to exit points and saved as a favorite so I can recall any of them at any time in case I need to punt.
Just have the So Cal Approach frequency handy for the south side of LAX and call them up once you are through the SRFA if they dump ya off...but in reality, I haven't heard of very many denials though LAX Bravo...they would rather have control of the planes in the airspace than a bunch of VFR flights on their own screwing up all the IFR traffic at all the So Cal airports!
It can defiantly be scary and intimating the first time down, but once you do it it is a piece of cake. Use the term "unfamiliar" when you need help and with going into Fullerton and ATC will point ya in the right direction. I always take the approach on the radio that FF is something that I want and know that they can boot me any time, so I am willing to do whatever ATC needs me to do to make their lives easier and keep me on. Have gotten many "thanks for your cooperation" from ATC which makes me all warm and fuzzy inside!