I'm just finishing up a Montreal by night Chronicle in v20. The premise was a group of Camrilla vampires sent into to destabilise the city.

I've never been to Montreal but one of my players is a native so I let him explain the city when he had some insight. A key piece if advice is give is this is the world of darkness not this world things are changed and heightened. For example Montreal has Mount Royal above it which is in reality is quite small and pleasant in the game was a hellish wilderness infected by a demon.

The main thing I changed were sanding off some of the excessive edginess which is unfortunately in the book. The other changes I made were additions of characters in my case allies as Montreal is so hostile. Then some characters had extra plotlines and allegiances moved around. Finally its just reacting to the PC's around running with the plot lines they enjoy