E.C.
It isn't hard. Just paperwork.
I live in the Cubberly district - but we're going to use Weaver Elementary in Rossmore. It is one of the best elementary schools in California.
It is harder to get released from LB than to be accepted by another school. So, doing an inter-district transfer (to Newcomb, Cubberly, Gant or Twain) is easier than leaving the district, but Los Al district needs kids so they will likely take you. Also - consider this - the LB high schools are really bad, and if you want your child to go to Los Al high, which is MUCH better, they cannot feed in from middle school - they have to be in a Los Al middle school to go there. So, think ahead, if you want Los Al high, you need to be in Oak or McAullife middle, so you might as well do a Los Al elementary school too.
That's my two cents.