[Alex]

Yeah, you can definitely get from LA to Oakland on Amtrak with no buses, but you have to take the Coast Starlight.

There is another option it will show sometimes (and often before the Coast Starlight when I've done it) that takes a bus from Union Station to Bakersfield and catches the San Joaquin from there to Oakland.

Note that if your destination is really Danville then in addition to getting off in Oakland (at any of the stops already mentioned), you can also disembark in Martinez, which might be easier if someone is picking you up (though not so convenient for connecting to other public transportation).