We use one of these.
https://www.amazon.com/Technology-Re...tectors+for+rv
It is an investment that can save you a whole bunch of repair cost if one of the questionable campground power systems tries to fry all your electronics.
I also recommend some type of lock, as these expensive devices are easily pilfered if left unsecured.
We use one of these. It keeps the protector locked to your power cord. I also use a steel cable to lock the whole thing to the power pedestal.
Surge Guard Universal Lock Hasp - TRC 34590-001 - Surge Protectors - Camping World
There are advantages to both in coach and at the pedestal. My thoughts are:
if the overvoltage is severe enough, it could set the protector on fire. I'd prefer to have it at the pedestal.
Ken