I just installed a 1000 Watt pure sinewave inverter in my class c. It already had a transfer switch for the generator. I added an additional transfer switch. I took the output of the first transfer switch (that would normally go to the distribution panel) and routed it to the new transfer switch shore power connection. I then ran romex from my inverter to the generator connection of the second transfer switch. I then added a relay to the hot wire of the convertor. The relay is a 120 volt normally closed relay, so when the inverter turns on, it opens (turns off) the converter. I also added a 150 amp circuit breaker between the battery bank and the inverter. All I have to do is be sure the microwave circuit breaker is off and the fridge is turned on to propane only and all my 120 volt outlets are hot. I may use a second set of output connections on my relay to disable the microwave automatically when ever the inverter is on. I like everything to be automatic and simple.