Any idea how long I should allow for getting from Copenhagen cruise terminal to the central train station? And how to get from one to the other? Also, when a cruise ship gives an arrival time, is that usually pretty accurate? Thanks!
Try the Copenhagen journey planner:
http://www.rejseplanen.dk/
You willl need to know the terminal that serves your ship. Central train station is København H (Hovedbanegård).
Check with your ferry operator. Some have bus transfer service to/from the port.