I can try to answer quickly.
It is absolutely necessary to ensure that the rail system is connected to effective urban transit solutions. In the case of the Toronto-to-Quebec corridor, obviously Montreal and Toronto have effective subway systems and metro systems that are able to connect people to the existing railway terminus. I would say cities like Quebec, Trois-Rivières and Peterborough do not have particularly effective urban rail services at the moment—or any urban rail services at the moment. Considering how those could be connected to a future intercity rail system seems very important.