Originally Posted by dretired
I would plug the 30 amp cord into a 30 amp socket at the pedestal..and watch my use
That's what I always originally thought the OP meant he was going to do. Hook a 30 amp extension cord to his 50 amp RV cord using a 50 amp female to 30 amp male adapter, then plug into a 30 amp outlet.
I guess we needed a little more clarification on how he planned to hook up everything, but I didn't see any problem (outside of being limited to using 30 amps of electrical items vs 50(x2), if he did it as described above.
EDIT: if I am visualizing this all correct, wouldn't the OP have needed two adapters if using it any other way (like trying to plug into a 50 amp outlet of the park pedestal)
Ex 1: (assuming the 50 amp power cord is the detachable kind) If he tried to hook a 30 amp cord directly to his trailer first, then he would need some kind of special adapter to allow a 30 amp cord to be plugged into a 50 amp RV......then he would need another special adapter to plug the male end of the 30 amp cord into the female end of the RV's 50 amp detached cord......before the 50 amp cord could be plugged into the park pedestals 50 amp outlet.
Ex 2: If he plugged the RV's 50 amp cord into the RV first, then he would need an adapter to hook the 30 amp extension cords female to the 50 amps cords male......and then another adapter that would allow him to plug the 30 amp male to a 50 amp female, then let him plug into the 50 amp outlet at the park pedestal.
Either one of those scenarios would be wrong, I also don't think either of the above is what the OP was envisioning, as he only stated using one adapter
EDIT 2: dretired, I now see you are the OP and already clarified yourself. Good deal.