I drove from Victoria to Toronto (and Ottawa and Quebec City) last year, and from Victoria to Ottawa this year (I'm currently in Toronto). The route this year was 2000 km shorter than last year!
It is actually very easy to do it now, as there are Superchargers all the way on I-90. There is only one missing now (Gillette, WY), so be very very careful trying to get from Rapid City, SD to Sheridan, WY. There is no way you will make it if you go the speed limit of 80 mph (128 km/h). A good alternative, and one that I had to use since Sheridan opened just as I passed, is to stay over at the Quality Inn in Buffalo, WY:
Quality Inn | Buffalo, WY | Electric Car Charging Station | PlugShare
They have two 80A HPWCs there. It spans the gap nicely.
It is quite feasible to make it from Comber, ON to St Joseph, MI on one charge (in the summer). There is no toll on I-94. It is possible to get through Chicagoland without paying a toll, but it isn't easy. The best route I think is I-94 until it becomes a toll road just north of Chicago. At that point take highway 41. Then you can either charge at Highland Park (Tesla service centre - LOTS of Model Ss on the lot!) or probably skip it and charge at Pleasant Prairie, WI.
Google Maps
It probably goes without saying that you can expect to hit epic traffic jams in Chicago, unless you go through at midnight or thereabouts.
The scenery on I-90, especially in Wyoming, Montana, and Washington state, is absolutely spectacular.
I actually plan to try going back through Canada, but it's really an all-or-nothing decision. There is no reasonable route I can think of that does a bit of both, unless you go through Duluth, MN. There's a Supercharger there now. That adds a lot of extra distance to the route, however.
- - - Updated - - -
Oh, also - if you want a break from the Interstate, take highway 12 from Pleasant Prairie toward Madison, WI. Fort Atkinson I thought was a particularly nice little town. It's a shorter distance, and more pleasant drive (in my opinion), but takes longer.