David,
If you get it to act up again, check the inverter control panel inside the coach to see if the AC Source light is lit. If the generator is running and putting out voltage, the lamp should be lit.
Voltage from the generator first goes through the transfer switch, then to the 50A main breaker in your AC breaker box. From there it is distributed to the various AC loads through the other breakers in the box; AC1, AC2, Inverter, etc.
If the AC light is not lit and neither AC is running; it's the transfer switch, 50A Circuit breaker, or generator (in that order of priority IMHO).
If the AC light is lit or not lit and one AC is running , you've lost one leg of the AC input; Transfer switch or 50A Circuit Breaker.
If the AC light is lit and neither AC is running the AC circuit breakers are bad or you've got a wiring problem between the circuit breakers and the AC units (probably ground). The light being on indicates the generator and transfer switches are OK.
The other possibility is that the generator is heating up while driving and not supplying enough voltage to power the ACs, but I think that would produce a generator shutdown and fault code.
(Above based on the wiring schematics for an 03 Marquis but should be applicable).
Good Luck, Steve