As you travel north from LA, you'll hit the lovely town of Santa Barbara, very upscale, lovely shops and nice beach. If you trek off the main street road to your east, you can drive through Montecito - huge estates that rival Hollywood Estates and in fact Oprah Winfrey lives there (and Michael Jackson's Neverland Estate is there), so its kinda interesting to see and the streets are wide enough for easy maneuvering.
North of there you will come upon the beachy town of
Pismo which is loads of fun. Theres a great RV park right on the beach in the small area of Pismo called
Grover Beach. Its one of the few beaches in the US where they allow you to go 4-wheeling on the beach dunes. You can rent sport vehicles - dune buggies - Jeeps - there, if you don't have your own. Downtown Pismo is your typical touristy beach town with all the tacky little gift shops HOWEVER there is a local hole in the wall sidewalk cafe' where you really should go -
The Splash Cafe. It's known in all the tourist books as the BEST place to get FRESH west coast clam chowder, made from clams harvested there. You can get it in a bowl or in a sourdough bread bowl. Sometimes the line is out the door and around the sidewalk, but its a great crowd to hang out with while you await your food! Across the street from that is one of MY favorite places to observe "culture" - Harrys (Biker) Bar. A big downtown bar with dance floor and usually live band, very colorful crowd and lots of bikers traveling through. If nothing else, go inside into the dark cool atmosphere and people watch while you have a cold beer. A nice initiation to Burning Man

-- Harrys
Continuing north from there, there is a MUST see, if you're not native to Ca. As you go through San Luis Obispo, you will see signs for the
Madonna Inn www.madonnainn.com . A huge white Victorian resort where each room inside is a "theme" room. The hotel has about 70 distinctly designed different theme room -- think of each room as a mini theme burner camp! Even if you only stop there to grab a meal in their over decorated, gawdy dining room, its really a weird and wacky piece of America I don't want you to miss!
If you have a couple of hours of time in your schedule at this point, you can cut off shortly after Madonna Inn to the east toward Paso Robles. WHY? Because at this point you will be at the "end" of one of the California wine valleys and stop at a few wineries for a tasting in their tasting room - I especially like Eos Winery (very nice whites - reislings, muscatos and full, fruity cabernets).
Of course, continuing along the highway headed north from this region, you should really make a stop in Monterey / Pacific Grove. The coast there is beautiful - huge rocks and boulders form the beach front - its very unlike what "most" Europeans think of when they envision California beaches - very wild and rugged and even in August, sometimes very foggy, cool and windy -- perhaps the last time you will be 'cool' for a week
There's lots to see in San Fran, too, even in an RV, but I'll leave that to the locals who will know that area much better than I.
Hope this gives you some fun ideas for some local color along your way!
Cheers,
Tobe