We brought over something from our boating experience . . . two way hands free headset communication.
https://cruisingsolutions.com/produc...aver-headsets/
Yes . . . they really are marketed as "marriage saver headsets" and they work very well for this purpose .
This means that when backing into a site, you don't have to find your "spotter" in the mirrors and interpret hand signals.
These also help to tune out the other friendly advice from other campers who think you should be doing it a different way.

Rob