I think this guy Manafort has a good handle on it. Trump is well on his way to 1237 which is really the only thing that counts. Speculating about second ballot voting is fun but not going to happen. I believe Trump will take CA.
I live here, and this is not a state you can win with Twitter and rallies. It is 54 separate elections, and for most of the state, you really have to know where the Republicans are and how to connect with them. For example, the latest Field poll shows Trump doing really well in Orange County and San Diego county - lots of GOP voters of the Schwarzenegger/Wilson variety, but only a handful of congressional districts. On the other hand, Cruz is leading by quite a bit in LA county - most district there only have a few thousand voters, but there are 15-20 congressional districts in the area. So if Trump wins big in the areas with lots of moderate GOP voters but few delegates, while Cruz wins big in the area with few GOP voters but lots of delegates - who has the advantage?