I live in SF but have done this stretch of PCH annually for several years.
I usually camp further up north but in this area I have stayed once a hostel in downtown, San Luis Obispo. I have ridden through Morro Bay many times and it is an attractive little burg that is heavily reliant on tourism and supplies a full range of accommodations from bare bones to luxury. It also has a state campground. I don't stay there because it is in the "middle" of a day's riding on my itinerary (I camp at San Simeon state beach and usually lunch in Morro Bay).
I have friends in Santa Barbara so don't camp when I get close to SB. Instead, I stop in Lompoc for the night. It has an older downtown but has the usual California expansion strip on the road out to the Federal Prison (Highway 1). For a night of a relatively cheap hotel stay (I use the Motel 6 on the edge of town) and good cheap eats, I like it. I've never biked to or stayed in Santa Maria. However, I don't ride up that route; I take Highway 1 all the way to Santa Barbara. The 19 miles south of Lompoc on Highway 1 is one of the trip highlights, for me.
I hope this helps.
Ray