Add second air conditioner to 30 amp RV

I would add that ALL pedestals require a 20 amp receptacle by code. But the NEC does NOT require the wiring to a pedestal to be sized for the 20 plus 30 amp receptacles to be used simultaneously and may be only #10 wire protected by a 30 amp breaker in a CG panel. You won't have 50 amps (30 + 20 @ 120 volts) available unless you're in a newer CG with loop-fed pedestals or a pedestal has 50 amps.

You would have no problem using a 30 to 50 amp adapter along with a separate connection to the 20 amp recept. other than monitoring the voltage.