I was there in September not sure about Winter. Worth checking, But if you can visit Brugges, I think that canal tour would be much more picturesque! The part of Ghent on the canal that's the most beautiful is the short 200meter area near Graslei and Korenlei. Beyond that it's just... a canal? I didn't do it, so I cannot judge. I did stay there though and it's beautiful. Dining, walking, photographing in the evening, etc. But for canal tour, definitely Brugges!

it is open all year round. See debootjesvangent.be

There is a small city bus turning round the city center and is free, is very interesting and the drivers are very good

You can get a train to Gent and it's a 40 mins walk form the train station or you can get a tram and it will take only 10mins.

Both sides are gorgeous, and go at night.

Graslei and Koreniei are the two embankments that face each other across Ghent's medieval harbor. There are guild houses on the Graslei side that hold historic significance to the city...and are quite picturesque. This entire area is a walking area and affords some of the best photo opportunities. Also, there are canal boats for hire in this area that are worth the hour to hour and a half time and about 6 Euro price.