One of the things I noticed when using the AC (and also the heat) is that the trailer often would be too hot or too cool. I researched and found a popular fix was to swap the mechanical slide type thermostat with a digital one.
Here is my version of that mod:
The original Thermostat has a High/Low Fan speed for the Air Conditioner. That feature is not found on most home type thermostats, and I ended up buying the Honeywell RTH2310 programmable digital thermostat. I initially installed it and just omitted the low speed wire.
After using the AC on my last weekend campout, I realized the low speed would be nice as it runs a little quieter and it would cycle on and off less in order to maintain the temperature better inside. I used a SPDT switch that takes the fan command from the thermostat and simply routes it through the contacts to either the high or low speed circuit. It was small enough to fit inside the case and only required a ¼” mounting hole.
I soldered short lengths of 18 gauge wire to the connections.
And then I covered them with heatshrink tubing.