Trump has already hired people in Sacramento and I think statewide in CA.
He hired someone statewide 2 or 3 days ago. The slates of delegates have to be submitted 3 weeks from tomorrow, and he has to find 338 delegates/alternates in that time. If that was statewide, it wouldn't be a problem, but they will have to go district by district to find 3 delegates and three alternates that can afford the $900 participation fee (that the campaign cannot pay for them) as well as the $3000-6000 cost to attend the convention, and are registered Republicans living in the district. In a lot of these districts, there may one be a couple of thousand Republicans living there, and a lot of the districts are lower income (South Central LA, central valley, etc.) So it will be a challenge for them.