Re: Contract
Your license is only valid in your state. To legally contract in CA you will be required to obtain a CA license. That would mean a trade and a law test as CA and WA dont reciprocate.
There are other alternatives though. You maight want to consider a partnership wih a CA license holder or hiring an RMO or an RME if the contract is large enough to warrant such action.
Unless the job is pretty good size or you are going to be obtaining more work in CA, it probably will not be justified.