Personally, I wouldn’t purchase a home within earshot of 56–but I know many people do–so, as others have said, it all boils down to your tolerance for the inevitable noise situation. Have also heard SR-56 may be widened at some point, only adding to the noise factor.
Also agree with ER with regard to not overextending yourself. I’m a native, and the job market here has always been very different from most any other area. As he said, it seems to be fairly difficult for many people to replace a high-paying job here should it be lost. As an airline pilot, my job has never been dependent upon the state of the San Diego economy, but, from friends, I understand it can be somewhat volatile.
Having lived, and having investment property in areas like CV, etc., I’ve always been amazed at how the majority of the residents in locations like this seem to perpetually stay the same age over a period of many years.
IMO, this points to the fact that there is quite a bit of turnover, and that many residents may not be able to stay and retire in San Diego (should they choose to.) Just an observation.
At any rate, I do wish you the best in your decision, and hope you find a great home for you and your family!