Man, now I’m getting homesick… 
Check this out for Santa Barbara Wine Country tasting. I’ve been to Napa and Sonoma and yes, it’s true that they have a lot more wineries and wine tasting rooms, but you can definitely make an afternoon out of Santa Barbara.
Historic Downtown Ventura is really fun and really, really close to the Ventura Pier. From downtown, you can walk to the San Buenaventura Mission and I believe there is also a museum on the same street.
Santa Barbara has a good little museum that I loved going to, as well as a zoo.
Serene might be a little hard to do in Southern CA (which is why we moved to CO), but there is a really nice beach that nearly no one goes to. It’s a great beach to do some serious beachcombing without running into a single soul for a couple miles. There is a power plant nearby and it’s an eye sore, but it’s still one of the few “solitude” beaches left in the area. This is a link to google maps showing you how to get there from about where you’ll be for the conference. You just go all the way to the end of Arnold Road and park next to the chain link fence for the military base (don’t worry, you ARE allowed to be on the beach, provided you stay on the right side of the fence)
This beach is NOT groomed or in any way cleaned, so it may have trash that washed up during the last storm, but it’s still a WONDERFUL experience. It’s one of the things that I truly miss about Ventura County.
Hope that helps a little… I’ll talk to my DH and see if he has any more suggestions. He lived in Ventura County for a 4 years with me, so he has a good idea of things to do too!