You could get to YQB through YUL, YYZ or (for something different) YOW.

To get travel between Québec City / Montréal / Toronto I thoroughly recommend VIA Rail (www.viarail.ca); I used to use the 'corridor' between Québec and Ontario quite a bit when I lived there. If you find yourself on board 'Renaissance' carriages (green in colour, and notable inside for their 2+1 seating throughout both VIA1 and Comfort classes) you'll be riding on board the cars originally built for the aborted Nightstar ... the overnight train that would have connected UK and Continental cities through the Channel tunnel, itself an evolution of the venerable British Rail mk. 3 coach still in use throughout the UK. The sleeper cars and a couple of seated cars travel most nights between Montréal and Halifax; the rest of the seated coaches supplement the older trains on the corrdior.

Veering even more OT, but still with regard to 'land sectors', are there still any Deutsche Bahn ICE high-speed trains that carry LH flight numbers, and can you earn/burn DC miles on them?