Dear Sailmc,
the 220 volt is no problem.
you can use a regular 50 amp 220 volt plug and hook right into US electric.
the air conditioners (3) and battery chargers (2) will run on 50 or 60 cycles.
the microwave, dishwasher, watermaker, and
washing machine have to be run on 50 cycles.
When you are plugged into shore power you don''t have to Make water, or do clothes.
the only problem would be the dishwasher or the microwave. I have never used the dishwasher. If i need the microwave i just start the genset for a couple of minutes. the genset start switch is right next to the Microwave.
With respect to the 24 volt systems.
if you look into bigger boats you will find many including Swan use 24 volts as the standard.wire sizes are half the size for 24 volts. consider what wire size you would have to run if you were using 12 volts and 1000 amps for the Bow Thruster!
All things i need are easily obtainable in 24 volts such as hella fans and jabsco pumps.
we also have a 12 volt supply ( provided as stock with the boat). we also have an inverter with one outlet which i use for my soldering iron and to charge phones and computers.
Fair winds,
eric