My camper is 30 amp. I carry a adapter to plug into a 50, only because often the 30 amp outlet is in such bad shape. I understand if there is a issue between the 50 amp outlet and my breakers I will not be protected. The cord could burn up, might start fire.
I also carry adapter male 30/female 20. I stand under anything plugged into that basically has no circuit breaker protection. So far, the only thing ever used for is the little polarity checker.
I can't say much about wiring of the pedestal, but can tell of my experience in state parks and COE CGs. Cold weather, I plug in the 30 amp, and thread a 12 gauge cord thru the tenting gap. I plug a heater in that cord. My AC unit must plug into a 20 amp outlet on it's own breaker to work. Not needing AC, a short 12 gauge cord for heater and mattress pad. This leaves the 3 other outlets, all on the same 15amp breaker, for all other loads. The only time a breaker has tripped is the 15 in the camper, when I plug in a coffee pot to heat dishwater and DW turns on her coffee maker. Even with a 3rd heater plugged in have never tripped the 30 on post.