If I were looking at a rig where 30A or 50A rv shore power is not available, I would start the generator. After a short start-up delay it should provide 110v power to test the TV, the Microwave, each roof AC unit, whether the Battery Charger is putting 13.6 Vdc or more into the house battery bank per my multimeter, and the refrigerator initial response (but not the cooling levels unless on for several hours).
Then, I would take a 50A to 30A dog bone connector and plug it to my 50A cord plug a 30A to 15A cord adapter to the dog bone and plug the rig to a shore power connection using a 15A extension cord.
All the above items should also work on the shore power.
Just do not try to run the Microwave plus AC or AC plus AC at the same time while connected to a 15A power receptacle. Also be aware that some units may have a 110v water heater. If it is on, it draws a lot of power.
If the house batteries have 12+ dcV charge in them, I would then turn on the inverter without shore power or generator power and test run a TV or the microwave (briefly).
More than once during your ownership you will need to power the rig in the above circumstances.