UCSD is probably the school lowest on this. San Diego is a beautiful area and the school has limited housing; the result is many students after frosh year end up living in areas like Pacific Beach or Mission Beach and commuting to school.
At all the rest students live on/near campus and with friends a walk or quick bike ride away will have much more of a college feel.
Since you live in the SB area it might be a better experience for your kid to get away from the home area.
Your son should be sure he understands the requirements for the major at each school and whether they must apply for formal acceptance to the major. At UCLA, for example, you must apply after taking the prerequisites (including 2 quarters of engineering-level calculus).