I have been on the Monarch prior to its facelift. It was a beautiful ship then and I'm sure it has only gotten better. Book your shore excursions early as they can fill up. If you are doing local sight seeing then often the local taxi system is a better choice and for much less than the bookings on ship.
And for your "Most important Question".... Drum roll please..... YES!!! The ship is registered out of Norway but everything on board is 110 volts just like the US of A.
I have only one other caution before taking this grand adventure. Once you have cruised you won't want any other kind of vacation.