20 amp shore power??? I missed that. It will not bode well for your ACs and other devices.
When we stored our unit on 20 amp we had to start the generator to use AC while preparing to head out. I might well run one ac and nothing else.
We have an inexpensive volt meter plugged in near the stove.If ac power drops below 105 we cut on the generator. AC load handling system will shed devices to save them. We can run two ACs on 30 amp but but system will shed loads including one AC if necessary. if the volts are normal between 110 and 130.
Don't try to run even one AC along with anything else on 20 amps.I think it takes 23 amps t start and goes down to 14 amps to run one ac.