
Move things around like this:
- TVS clamps forward overvoltage, protecting regulator
- Diode blocks TVS in reverse (TVS can be -A or -CA type) allowing very negative voltage
- MOV clamps excessive negative voltage for transient protection (optional?)
- 9V zener + 10k limits Vgs(on) (optional if "13.8" maximum + transient is within Vgs(max))
- Diode across C2 prevents reverse recovery from reversing U1 excessively (M1 will take some time to turn off, due to gate capacitance).
What environment are you working on anyway? 200V static is ridiculous. Is this like an industrial thing that needs to withstand cross-wiring faults (exposing 120/240VAC or other to control wires)?
The 13.8V sounds an awful lot like automotive standards, which you've severely misunderstood if that is the case -- the high voltages are transient only, and rather short in duration and high in impedance. They are easily filtered with LC filtering, and clamped with TVS. Only the slow stuff (cranking, jumping, reverse and load dump) are significant.
Overvoltage (whether load dump or otherwise) can be handled with a depletion MOS at this level.