Probably best to go in there IFR but ...
If I were going in there from Blyth VFR I would come across Blyth, Thermal, Palm Springs high, 8,500 or 10,500 and call Palm Springs approach (TRSA) as you are approaching that area just as a friendly call to help avoid rapid climbing, descending and squeezing through the pass traffic. After they let you go and you are through Banning Pass I always dropped down to 6,500 to stay above the class Cs in the Riverside area which run up to 5,500 and below the Class B later in this route. I would follow V388 (including the dog leg especially if it is hazy) to the Paradise VOR then V186 toward Van Nuys VOR. Before you get to VNY you will cross over Burbank and there will be some low mountains off to your left between you and Santa Monica (which has a VOR right on the field). Here is the tricky part. The top of the Burbank class C is 4,800 ft and the base of the Class B is 5,000 ft where they share a common boundary over those mountains. At any time between Burbank and Vay Nuys you can head for Santa Monica but you have to start your descent so that you are still above 4800 and below 5,000 when you cross the boundary. I usually start my descent so that I am very sure I am at 4,900, precisely, a mile or so before passing under the Class B floor then I drop after passing the crest of the mountains to get a little breathing room under the Class B floor. Santa Monica is a Class D so the airspace ceiling is low. The airspace is VERY BUSY and you have to be as sharp as you can be but it can be done by the book VFR without talking to anyone but Santa Monica.
One option after reaching Paradise would be to turn right to the Pamona VOR. The Pamona VOR sits on a hill just before the Brackett Airport and on the other side of it you will see the I-210 freeway running along the base of the mountains. If you cross over the "210" and turn left to head west again it will keep you outside the LAX Class B airspace. You will pass over El Monte Class D twelve miles west of the Pamona VOR. As you continue west the 210 runs fairly straight for a few miles then a low mountain comes up and the freeway splits with the 210 going off to the right and the 134 jogging to the left. The Rose Bowl is off to the left at this point and Burbank is on the other side of the mountain. After this the process is the same as above. If you don't feel good about your chances of getting in, turn around and head back East.
Often in the mornings, there is a low stratus layer over the coastal airports that is usually burned off by noon and you can bet on landing toward the ocean so late in the day the sun angle can almost blind you. An early afternoon arrival would probably be the best time.
You sound comfortable with the idea so I assume it won't be a problem but remember any mistake one pilot makes, hurts us all more than ever these days. This is all from a good ole boy in the middle of the country so take it with a big dose of salt. Be careful out there.
Bob Axsom