You will be docking at the Royal Shipyard, the Segways are right there for you. I have not tried them, but you are correct everyone looked liked they were have a great time. I don't know what Harbor nights are....please tell me. The Summitt was a pleasure, and you can read a review I just did under Celebrity titled...
"Just back from the Summitt" it may help a little. You won't go wrong. Don't be nervous, I booked the sister ship "Infinity" to So American and have been on the Constellation twice...no complaints !! The weather should be PERFECT