The RT electrical is 30 amps. So plugging it in to the 110V at the house it is pulling how many watts with nothing pulled from the house electrical to the vehicle (microwave, clock, radio, etc.)? :) ...
The microwave is only going to be pulling amperage when it is cooking something. Otherwise the clock on it is going to pull a fraction of a fraction of an amp. If everything but the microwave clock and the light on the radio are off, I would guess you are pulling way less than 1/10 of an amp. But you are probably forgetting many other loads that come on when you plug in. Things like the battery charger, the converter, maybe the fridge etc. What exactly are you trying to figure out?