I trust you will want to see some of Montreal. Having lived there in the 70s my favourite spot is Mount Royal.
Where is your next spot? Route 17 across ON to the west. Detour around both Mtl and Ottawa. Though Ottawa is also interesting. Routes change over time.
I did a cross continent trip in 2015. Going I went north to Lac St. Jean and across to Route 11 and returning I headed south before (not much) Ottawa and then to the south shore of the St. Lawrence connecting with the Trans Canada at QCity. (also to see at least a day or 2s worth).
Going I worked north after Thunder Bay and around Winnipeg with Hay River, NT the goal, then south again into AB across to BC and north to Whitehorse and across to Skagway, AK. Skagway was a suggestion from Whitehorse residents. It was a very good one. Skagway is different than many towns or cities. Good numbers of wildlife by and on the highways!!
As soon as I got into MN every local I talked too started directing me to Vancouver and I had to say, no I want to go north, I've already visited Banff and Lake Louise..... Pretty well, I set out to visit medium popular places, not the big names. I didn't want to be crowded by too many wheels.
My biggest name place and top choice for site to visit was Tyrell Dinosaur Museum. Give that about 10 *s. Very special. Some US residents come to Canada to make Tyrell their two week holiday period.
There are nice cgs out and about. N. Shore Lake Superior also.
I'd say 6 weeks is minimum for such a trip. When I lived and worked out of Sudbury, there were people who would go west for 2 weeks one summer and east for 2 weeks the next summer. Still short, IMHO.
:B