Canada is huge. So pick a type of location, and possibly a type of sight-seeing. I.e. History, nature, Fun, Informative etc.
But since you say you don't drive, then I suggest sticking to urban sight-seeing.
I know very little about anything west of Ontario, except that there is a huge dinosaur museum somewhere in Alberta not to far from Cold Lake. Also the West Edmonton Mall.
In Ontario there are a lot of wine tours you can take in the Niagara region (you sign up with a group and they bus you around to various wineries in the area where you get to taste the local wines, sometimes paired with local foods). Toronto is a large city with a fair bit to do. We just got an aquarium which I hear is really cool. Plus the Hockey Hall of fame, CN Tower, Royal Ontario Museum, Ontario Science Center, Canada's Wonderland, and the Toronto Zoo (We have Pandas now). Plus other sight-seeing things I still haven't done.
Montreal is really nice as well. There are some places to visit there. I've only been to Old Montreal and St. Joseph’s Oratory located on Mount Royal itself (the city was named after this landmark).
Quebec city is beautiful as well. Lots of history and beautiful architecture. Take a tour around the old city walls. It's amazing.
Nova Scotia has lots of beautiful campgrounds and historical locations you can visit. My favorite as a child was Port Royal (or Annapolis Royal, I forget).
As you can see, lots of choices, and I've only provided a couple.
As for travelling between cities, public transit varies a lot between cities and provinces. Though we do have our CN rail line on which our countrywide passenger train travels.
VIA rail offers various packages for different parts of Canada if you would be interested in any of those.
As for Hockey, every city/town in Canada has Hockey. It might not be NHL, but we have good players everywhere. And if you can't get out to a live game, if you travel during the playoffs, you can always find a pub/bar/restaurant playing the game on a big screen.
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