How cold should the air conditioning get the RV?

humidity is a very very small factor of the physics of heat exchange on the condenser part of the AC unit, but not enough to waste a sentence on. Humidity does matter as far as how cool will feel comfortable though. More humid = needs to be cooler.

All my campers have had one AC unit and have been more than enough to cool, even in 113 desert sun, though they ere not big spaces either.