I booked this cruise/crossing at the last moment, when I was able to get a good rate as a solo traveler. I was able to get a ticket to Athens using Amex reward points, which eased my conscience about taking a second cruise in 4 months! (I just retired in June and am still celebrating). I flew into Athens the night before and the cab driver my hotel had booked for me was waiting with a sign; he delivered me quickly and smoothly to Piraeus. The Piraeus Theoxenia Hotel was very comfortable, the staff was very helpful, and the included breakfast offered many tasty options. At my request, the desk called the same cab driver for me the next morning for the short ride to the port.
Embarkation was smooth through my check-in with HAL, but as it was a national holiday, the Greek government had provided only one passport clerk to inspect all 800 passengers' passports. That line got very long! Moreover, the shuttle from the building to the ship was hot and slow to depart - but soon enough I was on the ship and unpacking in my comfy stateroom.
I always book an outside cabin on a lower deck amidships, and Prinsendam's staterooms in this category are extremely comfortable. In particular, since the ship does long voyages, there is a roomy walk-in closet - plenty of storage, even when on a previous crossing I shared the stateroom with my sister. As it developed, there were quite a few days of strong winds during the cruise, and between the rocking of the ship and the comfiness of the bed, I slept extremely well!