If you look in the archives you will see this subject flogged
repeatedly. The biggest issue is how to prove the aircraft was outside
California---hangar bills, fuel receipts, etc. all help your situation.

But if you are going to be 3 months without your shiny new toy anyway,
why not use it as an opportunity? Buy a great plane with a run-out
engine and overhaul out of state. It's not quite the same as having the
state pay for part of your overhaul, but the net result is similar.