Quickie synopsis:
Montreal: go upstairs over the Station and check out the Queen Elizabeth Hotel, it's famous, the Beatles recorded " Give Peace a Chance" there and John and Yoko did their famous " Bed In for Peace" there! Sounds like you don't have time for Old Montreal or Mount Royal, but the Station is nice, the First Class Panorama Lounge is really a good one! FC on VIA is sort of like FC Acela, nice ride on the Corridor to Toronto!
Toronto the Good: ( Canada's New York)
The subway runs right into Union Station/ the Hockey Hall of Fame is a couple of blocks away, worth a visit!
Yorktown: Toronto's Greenwich Village with Clubs, Cafes etc. Lots of famous people hung out/lived there,but its definitely gone upscale, but worth a look,,! The Panorama Lounge is also Nice here while you wait for the Canadian!, its like a Nice Club Acela with friendly attendants!
The CN Tower ( like the Space Needle or Sears Tower)is close to Union Station as is the Sky Dome Stadium ( now called the Rogers Center, Canada's Time Warner) which as a Hotel inside the Stadium! Its connected by an indoor walkway but if the weathers nice it prettier to walk over outside!
Vancouver;Pacific Central Station is on Eastern side of downtown/the Sky train ( elevated Light Rail Station) is right out front/ you can ride it all the way to the Airport but you will change trains @ the Station @ Canada Place where the Cruise ships dock right in the middle of downtown! This place is an old Rail station but has a food court,Stores, the Sea Bus Terminal ( part of the Sky Train/Bus System, you cross English Bay on Ferries to North Vancouver)
The Airport is out on sort of an Island on the SW side of town, you'll go through West Van ( Gay Vancouver like Castro in San Fran) and Kitslano ( Vancouver's Height Ashbury in the 60s but now Very Chic!) on the way, easy trip to the airport!
Hope this helps, Downtown Vancouver isn't that Large but Toronto and Montreal are huge, everyrhing you need is right downtown!!! Specific questions?