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For good fast food, try In and Out. If you're driving and need a quick stop, In and Out is light years beyond McDonalds, Burger King, or anything else.One more suggestion - I'm not sure what your plans are for transportation, but I've found the drive from LA to San Diego to be a nightmare, every single time. The last time we were out there we took an Amtrak train, which worked out really well. From the Amtrak station in San Diego you can take a trolley to the Zoo or just about anywhere else.