
My ultimate goal is to depart Runway 24, Southwest bound towards PDZ to join the 278 Radial outbound towards El Monte airport (KEMT).
Departing VFR, I believe I would be ok by climbing to 2,500, I would slip underneath the Ontario Class C, and the LAX Class B. My question is in regards to the immediate departure. Should I contact Riverside Tower for Clearance to transition their Class D before I take off or after? As soon as I exit their Class D, I'll have to immediately call Chino Tower and request to transition their Class D. Is these the steps I would have to take?
As far as IFR is concerned, I read in the AF/D for KRIR, that for IFR clearance, I need to contact Socal Approach on 135.4 as shown below. So I get a clearance from Socal Approach, depart on Unicom, since Flabob is a non-towered airport, then immediately call Socal, or do I still need to contact Riverside first?

I hope everything I said makes sense...
Thanks,
Chris