The trans-continental berths/sleepers are usually prohibitively expensive (i.e. more than flying!). If I was you, I would check early and often for the Express Deals Discounts on the viarail WEB site. With some effort, you can piece together a reasonably-priced itinerary - and - see the places you want!

I suggest you take a pass on Edmonton, and visit Jasper instead. Also, time permitting, check out the 2-day side trip from Jasper-Prince George-Prince Rupert. Breathtaking!

I am also not sure about visiting Winnipeg? The Forks are nice, the downtown has interesting architecture, what else? (The new Canadian Museum of Human Rights opens in September).

Definitely plan to visit Quebec City, Ottawa (en route to Montreal!). Feel free to PM me if you want more specifics.

The scenery on VIA east of Quebec City is not very interesting so you may want to skip it.