I know the San Lorenzo Mayfair and Mervyns very well as I grew up there. In fact, I could probably draw a map of the store, from my memories as a little girl.
So here's the layout of the area (circa 1960-68 or so): The stores were contained in somewhat of a "U" shape, with the top being the main drag, Hesperian Blvd, the left Paseo Grande, the bottom Via Arriba, and the right Via Mercado. On the other side of Hesperian was (is?) the Lorenzo Theatre, which was the only theatre in the immediate area and a popular place, showing daytime movies for kids during the summer. The middle was a large parking lot, in which Santa arrived via helicopter every Christmas season!
The original Mervyns took up almost an entire block of the street on Via Arriba. And this WAS the original Mervyns, opened by Mervyn Morris (not Mr. Mervyn!) This building has since been demolished due, I believe, to structural issues. It had a second story with merchandise (linens and fabrics). At the end of Via Arriiba (to the left, as you're facing the Mervyns) was a 10 lane bowling alley, below street level, and extending below the Mervyns store. Yes, this is where I learned to bowl! I think it was called Lorenzo Lanes. I don't recall when that closed. Above this was a dentist's office.
When they demolished the Mervyns building, they were surprised to find the remnants of the bowling alley.
On Paseo Grande, far left end of the strips of stores, was the Mervyn's toy store, which also carried phonograph records. This was separate from the main Mervyns building. To the right of that was the Western 5 and Dime, which carried absolutely everything under the sun, including hamsters, fish, books, toys, crafts, candy, and most likely lots of other things that a kid wouldn't pay attention to.
Next to the Western 5 and Dime was a bakery, barber shop, and a jewelry store (not sure which order they were laid out).
Oh yes and to the left of the Mervyn's toy store (corner of Paseo Grande and Paseo Largavista) was a gas station, and an ice cream store (separate building, bigger than a kiosk but not much) - I think it was called Lois' Ice Cream.
And on that block was the Mayfair Market. Entrance was to the far right, and also an entrance from the back. Inside the store, to the left was the separated liquor area, also selling magazines and candy. This had a separate register. Staight inside was the produce, and the meat area was far back, with the actual meat packaging visible behind glass. You could see them grinding and cutting and packaging the meat! Yes, they gave out green stamps (or blue stamps, one of those). Everything else I remember probably isn't of interest to anyone.
And at the corner of Paseo Grande and Hesperian (Mayfair didn't extend all the way to Hesperian), was a shoe store. Thom McCann's, perhaps? It had a lovely large display curved around the corner - remember those large displays?
This entire area was the central shopping for San Lorenzo Village. There was a second area elsewhere in the village (Bockman and Via Chiquita), but looking at Google Maps, that too has been demolished. San Lorenzo was post-war housing, basic cookie-cutter homes, 3 bedroom, 1 bath, 1 car garage, all one story, with a sycamore tree in front. Moms were home, often the dad had the only car. 100% white, I'd say 90% households had kids. The Mervyns and Mayfair supplied most of the households. They were also closed on Sundays! Hard to imagine now, isn't it?