Some things to be aware of:
First, check the AC manufacturers specs and you should find that a min. wire size of #12 is required and also for runs above 50' (overall) min. #10 is required. Marinco/Park Power makes a 20 amp power inlet that would be good for this.
Good voltage is key. Check the voltage when the AC units are running. Voltage below 105 will lead to premature failure. If it gets down to 105 (on shore power), shut off the AC units and wait for it to go back up (if it does) or get a Hughes autoformer. Use a plug-in voltmeter inside or install a permanent wall mount. Better, install an EMS so that power will be automatically disconnected if too low (except that the AC on the 20 amp recept. would need it's own EMS for this to work and same for an autoformer).
Voltage at your camper will depend on how good the CG/RV park wiring is, how old it is and how long the runs are between a pedestal and CG main supply. AC units draw more current the lower the voltage gets and running two simultaneously could substantially increase voltage drop, especially in older CGs that have panels distributed around the property with individual runs to each pedestal. (Newer CGs have loop-fed pedestals). An older 30 amp pedestal could have just #10 wire supplying it and then you'd be trying to run up to 50 amps on it. A 30/50 amp pedestal would be fine.
Note that the NEC does not provide for simultaneous operation of a 30 & 20 amp receptacle in a pedestal for load calculations and sizing of wire from the pedestal to main supply.
Just because an AC unit(s) *seems* to start and run okay, it doesn't mean that the voltage isn't too low and causing damage to it/them.
