I see that both of the former Canadian trips are back for 2017. The TransCanada Railway trip was one I took, although not with GCT. The scenery was beautiful, going either way. And the Canadian Maritimes was also enjoyable. We couldn't get into a GCT tour for that, so we went with someone else. But there's a lot to see and learn about. When we took that one, it left from Boston by bus to New Brunswick, I think it was. We lucked out with the weather. It was cool, but it stayed sunny the whole trip.
I recommend both of them, depending on how much time you have available.