Don't know if you're a fan of canals? If not, there is a cycle highway between ghent and antwerp but I haven't cycled it yet / don't know if it's finished yet.
One day in Bruges would be more than enough. I'll ask my brother-in-law for recommendations in Bruges, they live closeby.
I've found my ghent-hook of holland route but it's worthless as it follows the coast. If you go ghent-antwerp-rotterdam there will be better routes.
Brugge - Gent is boring if you take the canal.
This one via Knesselare is better: http://brouter.de/brouter-web/#map=12/51.1478/3.4476/OpenStreetMap&lonlats=3.228736,51.211192|3.72664,51.05284&profile=fastbike
Gent-Antwerp is a beautiful canal (rough gpx by someone else https://www.routeyou.com/nl-be/route/view/97822/fietsroute/gent-antwerpen) but that might be because I'm local...
Don't know if you're a fan of canals? If not, there is a cycle highway between ghent and antwerp but I haven't cycled it yet / don't know if it's finished yet.
One day in Bruges would be more than enough. I'll ask my brother-in-law for recommendations in Bruges, they live closeby.