The Malibu and Hollywood option:
If you are traveling south into Southern California by way of US 101 and have traveled through Santa Barbara and Ventura,think about getting out to the coast and travel down through Malibu and Santa Monica. Turn south on Rice Avenue off US 101, travel 4 miles to CA 1 (Coast Highway)and head 30 miles easterly toward Malibu and then another 10 miles into Santa Monica. This stretch of coast gently arcs to the right, providing spectacular vistas across Santa Monica Bay of the Los Angeles skyline and the hills of the Palos Verdes Peninsula.
This is the stretch of coast that pops up in car commercials. Its where Jay Leno has been seen promoting the Tonight Show in his blue Cobra and its where Rockford's trailer was parked. The surfers, tourists, and babes hang out in the beach parking lots along the way and it is where Two and a Half Men is set. The beach homes crammed between the highway and the surf line are the residences of the Hollywood rich and famous. This is the iconic stretch of beach that is Southern California--well, as much as any single location can represent a much larger region.
Along your way, eat at Neptune's Net on the inland side of the highway up on the west end of your journey (its the first significant building you encounter) or at Gladstone's at CA-1 and Sunset Blvd at the east end. There are plenty of other choices, of course, but these are both seafood restaurants that are popular motorcycle hangouts--particularly Neptune's Net.
Once you have traveled the coast, you have two great options. Once in Santa Monica, watch for the sign for I-10 and turn east. From I-10 you can take I-405 south toward Long Beach and the San Diego. Or, before getting all the way to Santa Monica, turn east on Sunset Blvd and follow it 15 miles through Pacific Palisades, the Hollywood Hills and Hollywood to US 101 (the Hollywood Freeway). You'll cross Sunset and Vine in Hollywood and get a street level view of this tourist-packed region of Los Angeles. The front of "77 Sunset Strip" is at 8524 Sunset Blvd. (remember Kookie and Cricket?). Jimmy Kimmel's studio is on Hollywood Blvd. as is the Kodak Theatre (Hollywood runs parallel to Sunset, a few blocks south).
If you have never seen Malibu and Hollywood, consider this option. It will gobble up time, that's for sure, but if you live 1500 miles from here and your opportunity to ever see this important part of Americana is very limited, then spend the time.
I recommend that you do some web research to prepare yourself for this day of riding and see the sights. Sometimes being a tourist, rather than a long distance motorcyclist, makes sense.