"What do the people in the newer rigs do that have 50 amp connections?"
We stay at newer RV Resorts.....just kidding
I've never run into a problem at any of the RV Parks we have stayed at.
However I do remember being in my Dad's MH with dim lights due to low voltage on the campground power line.
We have four batteries and an inverter to run off of so I would probably unplug from the campground power and run off of batteries or generator (if A/C is needed) until late at night and then plug back in to recharge the batteries.