We did this as our honeymoon.
Stateroom: We had a room with a balcony. It was smaller but the perfect size for two people. We didn't get to use the balcony much because the sun didn't really hit it much but it was so nice to have anyway. It was very clean and the room attendants were so friendly! There was also lots of storage to hang up all your stuff. The staterooms had lots of plugs and options for European and North American plugs. It had a hair dryer in the room so I wouldn't bother packing that.
Embarkment: The embarkment was in Barcelona. There was a a lot of people at the cruise terminal but we probably registered, bags dropped off and on the ship within 45 mins to an hour max. Super smooth process and a lot quicker than I had anticipated. It was our first cruise so we didn't know what to expect really.
Small but lots of storage and very clean.
Beautiful town. Loved that they had a little boat to take us ashore and that were able to explore.