Your best bet is to check the Rome to rio website. They are good at posting distances and transportation modes.
Everything depends on your time.
If you are arriving on the day of the cruise and want to do this before boarding, then I would strongly advise against doing it.
Most likely You would be taking a bus, and then the water bus . And the bus drive is about 90 min each way. Anything can go wrong.
But check the site I mentioned, in case there are other better options.