Cheapest way to get to the west coast

Hi
We'd like to do a road trip from San Francisco to LA, Palm Springs and Vegas - which we've done before a couple of times, but not for a few years. We can't really afford the prices currently being quoted direct to SF in September, and wondered if it would work out cheaper if we flew to, say, New York with Virgin and then got a domestic flight?
Any advice would be gratefully appreciated
We'd like to do a road trip from San Francisco to LA, Palm Springs and Vegas - which we've done before a couple of times, but not for a few years. We can't really afford the prices currently being quoted direct to SF in September, and wondered if it would work out cheaper if we flew to, say, New York with Virgin and then got a domestic flight?
Any advice would be gratefully appreciated
