Good luck finding a place to benchrest. Can't remember if South Bay has facilities for it, or matches. Left there in '91 and have only shot at an indoor range there since with my brother.
You might find one over in Imperial Valley or up in Riverside/ San Bernadino, or maybe even Orange counties.
https://www.shooting.org/Ranges/California/San_DiegoThis one might work:
https://www.shooting.org/Ranges/California/Alpine/Lemon_Grove_Rod_Gun_ClubThis one about 45 mins +/- from Downtown SD in a nice area of the county.
Poke around on the internet, you may find some more.
Good hint from FatCity there, I forgot about CalGuns
Geno