Genoa Shore Excursion - Portofino?

[Longwood50]

We will be cruising on the Celebrity Infinity and have a stop in Genoa for the day.   We are thinking of doing the on and off bus in Genoa and perhaps a trip to Portofino.  
It looks like there are two ways of getting to Portofino one being water taxi and the other by train.  The bus is also available but way to many transfers.  For those who have been to Genoa what would you suggest?  Is it worth it trying to see both Genoa and Portofino in the same day?   It appears that the water taxi's stop also at San Fruttuoso.   However it does not appear that they stop there for very long.  Any suggestions of how to go and what to do would be appreciated. 

[MANDMTRAVEL]

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