We have been on the Constellation before and she is a nice ship. Very clean and well kept. Our cabin in Concierge was excellent as was our balcony.
Transportation from Venice Airport: airports-shuttle-express.com. 50 euros for 4 people
Celebrity was not really giving maps at the ports unless you went to the Guest Relations desk and asked.
Our cabin was wonderful. Centrally located. Very nice as was the balcony.