From cruise port to Boatshuttle service

Which city's cruise port are you referring to?

Copenhagen

we are expected to dock at Langelinie Pier Thanks

I haven't taken the boat shuttle service. It may be a really good option. I have taken the train from the port. Depending on where exactly your ship is parked, it can be a longish walk. There are painted lines on the pavement (I think they are blue) you can follow to get out of the terminal. Once out, the train stop is about two blocks away. They run regularly. We used a Copenhagen card so don't know if the ticket machines take a credit card. I'd guess they do, but don't know if they want a chip and pin card. I'd suggest one of two itineraries. Take the train to the Norreport stop and walk from there - see Rosenborg palace (and crown jewels) then Nyhavn (maybe the boat tour). If you have more time, you might also see Amalienborg palace. To get back, you can take a taxi or catch a metro from Kongens Nytorv (adjacent to Nyhavn) to Norreport (I think just one stop), then train back up to the cruise terminal area (Nordhavn). Take the train all the way to central station. From there visit some combination of the National Museum and Ny Carlsberg Glyptotek, City Hall and/or Tivoli Gardens. When it's time to go back, catch the train to Nordhavn. I don't think you have near enough time for both or to venture to sights further out of town (Helsingor, Fredericksborg or Roskilde). One of my best tips for cruising is get to the exit ramp slightly before docking so you're off and running before the crowds (also pack a snack from the ship in case you don't have time to stop during the day).