I don't know San Diego well enough for local landscapes. I imagine there has to be something by the coast and harbor. The zoo is great, and I do think you would get some landscape shots and enjoy the animals at the wild animal park (I prefer it to the zoo). Just looking at some pictures, it looks like there are some great vantage points of downtown San Diego from near the North Island Naval Air Station.

It is far (~3-3.5 hrs) but I've been to Joshua Tree National park. You could get some epic landscapes there. A little closer, but I've driven to the Salton Sea and the Hills/Mountains on the route provided for some good landscapes. I believe it was Rt 78.