I've done this ride from SF to Laguna Beach many times and down to San Diego once. Here are my thoughts:
I used the Hwy 1 routing to Guadalupe south of Oceano/Grover Beach. Once, I took the section using Valley, Los Berros, El Campo, and Halcyon. I found it longer and no more interesting than going up the hill and directly to Guadalupe. The ride up the hill (Hwy 1) can be a bit hairy as it is shoulderless and steep. But, it is also short and straight so people can see you. That said, don't do it without a mirror and willingness to pull over to let trucks (mostly pick-ups) go by. I'd suggest staying on Hwy 1.
Here is a quote from
my journal of that trip:
Just past Oceano, there is a plateau that has to be climbed on the way to Guadalupe. There are two ways to deal with getting up the mesa. In the past, I've simply humped it up the narrow, two-lane road that is Highway 1. It is a low-gear grind on a not very busy road. But, when farm trucks go by (at speed), it can feel a bit dangerous. And, going uphill, makes it harder not to swerve unexpectedly.
The other route involves going around this hill and is the route featured on the ACA maps. I decided to try this
indirect route. Thus, instead of turning right and riding up Mesa View Dr., I turned left onto Valley Rd and then right onto Los Berros Rd.
This road was deserted and had it's own ups and downs. Also, it was past noon, getting hot and I was sweating profusely. I stopped at a store and deli, the only bit of commerce I saw on this stretch of road, and took down the first part of the sandwich I was carrying.
Eventually, I turned onto Willow Road for the climb up to the top of the mesa. Not only had I ridden about twice as far, but the climb was no easier nor much shorter than the other, much more direct route. One plus it had was that there was no traffic. Once to the top of the mesa, I still had a long way to get back to Highway 1 and the wind was in my face the whole way.
When I did finally get to Highway 1, it seemed like I had done a lot of extra riding for not much distance on the map. I find it hard to believe that I will bother with this longer route next time I ride down this road.
I also would take Harris Grade Road into Lompoc. It is a bit of a hard push up the hill. It is very curvy but always low traffic when I've been on it. The biggest issue is motorcycles, and the occasional sports car, being driven way too fast on it. These can both be heard far away so it is easy to be prepared for them. I found Hwy 1 to be more effort and far less interesting. It takes all the traffic that Harris Grade Road used to. There is a wide shoulder, but it certainly isn't any easier. Further, the shoulder on Hwy 1 near the base is all torn up due to heavy vehicles. From the top of Harris Grade Road you can just about coast into Lompoc. Here is my description of
the day I rode from Oceano through Lompoc on Harris Grade Road, including some photos of Harris Grade Road, itself.