Jeremy,
In the 2nd storage compartment up on the ceiling you will find the "transfer relay" I think it may say "Esco" When you remove the cover you will find the wiring from the generator, the wiring from shore power cord and the wiring that goes to the circuit breaker box in the bedroom. The default position of the relay is "shore power". When you start the generator, there is a 30 second time delay and then the relay engages and disconnects shore power and connects generator power to the outgoing wiring to the circuit breaker box. If you are comfortable using a meter, you can check the a/c voltage from the 2 sources and check the voltage going to the circuit breaker box. It is not unusual for this transfer relay to fail on a coach this old. Let us know what you find. Fred