Watchyourspeed, I've deleted your last post simply because the photo was too large. Would you please resize it to 600 x 800 at most, and repost it. That said, though a convenient shape, and route you have shown will take you needlessly over some very unwelcoming territory for a 172. The center of Northern Ontario is not at all welcoming to single engine landplanes. I would strongly advise against the route through the north of Ontario, as there would be very little benefit for a large risk. I've flown hundreds of hours through there, and as a result would recommend following the north shore of the Great Lakes, then to Winnipeg following the highway. Understand that in most of Canada away from the US boarder, it is possible to fly [a 172] for several hours, and not see or cross a single sign of humanity if you don't follow a highway, or other established route. Your really do not want to be there in poor weather/night/problem with the plane. Pilots have crashed within 5 miles of the highway, and their remains not found for years.
And, the mountains of western United States demand great respect. Routes in that part of the continent should be planned with the aid of people with local knowledge. A 172 might be very challenged by high density altitudes. A lot of the area you showed would require serious desert survival capability.
I have been fortunate to have flown VFR every province, territory and state in North America, and they all have their charms, but serious caution is required for regional topography, and local weather phenomenon.
As silly as it sounds, for what you are proposing, before using the aviation chart, plan with a highway map! Perhaps you'd like to repost your desired route, adjusted with some thought to "locale", and there will probably be some helpful comments about segments.