Below are descriptions of some of the cities in San Diego County from T.S. Van Dyke's The City and County of San Diego (1888). Keep in mind that most of them were barely towns and that San Diego County was much larger then. Imperial County and most of Riverside County came from San Diego County.
"A few miles farther up the shore is La Jolla Park."
"Just around the opening of Soledad Valley upon the sea lies the handsome seaside town of Del Mar, with some 300 inhabitants."
"Carlsbad, a new watering-place with a mineral spring whose waters are attracting much attention. A few miles north of Carlsbad is Oceanside, a fast growing seaside town of over a 1,000 people."
Northeast of Temecula, 25 miles from the coast, is the Laguna Rancho, which contains 5,000 acres and surrounds the county's largest lake.
"By this lake is the thriving town of Elsinore with nearly a 1,000 people, with Wildomar near by well on the road to overtake it."