Bummed, barely used AC already Not Performing.

I would second the observation that it is essential to check the voltage level during the operation of the unit, since with the symptoms described, this seems the most likely culprit -- voltage drop.

Since it takes so long for the compressor to kick in, low voltage seems likely. Addition of a hardstart capacitor might help this symptom, if low voltage is not the issue.

RV AC units are not designed to be recharged. If the unit has lost refrigerant, it should be replaced.