You will see a few paths at different locations in San Diego... including the Bay Shore Bikeway that rings the bottom of the Big Bay from Coronado through Imperial Beach to CV and National City up to the edge of San Diego.

The google feature is in beta, so sometimes it assumes a sidewalk or dirt path is a bike path.

Real San Diego bike maps are available here: http://www.sdcbc.org/Maps-Routes.html

If you have a high speed data connection and a good printer, you can download this PDF:
http://www.icommutesd.com/bike/documents/southbikemap_web_000.pdf

You might also try one of the bike map sponsors such as Holland Bikes on Coronado...
977 Orange Ave, Coronado, CA 92118
(619) 435-3153

And hey, there is always Coronado Brewing Company, in Coronado, if you happen to be on Coronado Island... about 10 blocks north of Holland Bikes.

Coronado Island is a fun visit anyway... fairly flat, 25MPH speed limit, except on the main road through town, and you can reach it via a ferry ride (with your bikes) from Downtown... and as a sailor, any ride on a boat is a good thing.

Enjoy!