Trans Canada Highway

[Jim.B1]

The Trans Canada Hwy is the major route east/west across Canada. There are gas stations all along the way, even in some of the more rural parts you will still be able to find fuel.
Like any vehicle, just don't run the fuel so low that you are in a panic when it gets too low.
Yes, the fuel prices in Canada are higher than in the US, but don't forget, the US dollar is also 35% higher than the Canadian dollar so things average out.
The scenery through northern Ontario along Lake Superior is spectacular.
The only toll road in Ontario is Hwy 407 through Toronto (no fuel on this road) and you can avoid taking it by taking Hwy 401, but, the 407 has much less traffic so it is a faster route.
I will agree the Prairie Provinces may not have lot of scenery, but if your intent is to see Canada, then see it.
Welcome, and enjoy your vacation in Canada.

[Teamfoxy]

We did part of that route a couple years ago. North through Sault Ste Marie, up the Superior shore to Wa WA and then back down and across to almost Montreal and came back into the US near the NY/VT border. The roads are good and fuel is plentiful. We had tire trouble near North Bay and the people were great to deal with and very fair on pricing. The provincial parks along Superior are well cared for and beautiful. We didn't find the roads to be bad at all. Apparently the people who said that have never driven in IL or MI.