Electrical questions

There is a ground cable from the generator to the RV frame that can get corroded and make poor continuity/contact. There may be a switch on the dash that connects the house battery and engine starting battery in parallel to help start the generator or the engine. That clicking sound with no cranking means that the generator starter motor is not getting enough power from the house battery which quickly runs down with attempts to start the generator. If your house battery and engine starting battery are both fully charged and you press the emergency start switch, the generator should at least crank rapidly for a short while. If you start the truck engine and let it run for a while then attempt to start the generator from the switch on the front of the generator it might start and run if fuel system is clear and you have more than 1/4 tank of fuel. The start switch on the front of the generator has less resistance than the remote wired generator start switches. You may have to install a new fuel filter and/or new carburetor. Generators need to be run frequently and for an hour or so or they become balky at starting, surge, etc. Run generator with no load for 10 minutes then turn on roof air conditioner and let run for an hour every month or so to keep generator reliable. Generator should operate the roof AC and microwave oven together if working properly. BTW, check cleanliness of connectors at your house batteries, remove any corrosion and tighten securely.
Make sure connections at the converter/charger are tight and that house batteries are getting charge current from the converter charger. Keep electrolyte levels above plates in batteries with distilled water as needed.
Being anal about 12 volt systems and generator is necessary for off grid operations. Most of the appliances rely on 12 volt power for electronic controls, your furnace blower must have 12 volt DC power.