Whats the best way to run cabin acceseries like microwave or fridge? Big inverters, small generaters or? What rules are there for generaters on a boat?

first, if the generator is going to be in the engine compartment, it has to be a marine gen. watercooled and spark protected, you can run some stuff with an inverter, but they are not very efficent, you would need some good large bat's for like the microwave. fridge's don't use a hole lot of power, generally you will run them on DC unless the genset is running. you can put a small generator on the back deck to keep batteries charged and to run larger AC stuff.