Good analysis, though you are only looking in the one direction. What about large population centres that already have a significant "installed base" of customers who may want to *go* somewhere not currently served? This would be the reason why Superchargers were built in Barrie and Huntsville and Parry Sound, for people *leaving* Toronto (to cottage country). In this case: Edmonton has roughly the same population as Calgary, and I'm sure they resent having to go through Calgary to go anywhere.
The Yellowhead highway west of Edmonton goes through some pretty stunning scenery, e.g. Jasper. It's very difficult to objectively prioritize routes unless you first decide what's important.
In any event, Tesla has already posted what they plan, and that's the Trans-Canada highway all the way from the existing "trailhead", so to speak, at Calgary, to Halifax (Enfield), via highway 17 (Sudbury to Ottawa). All "target opening in 2018". It's fairly certain that any other routes will happen later. As for what gets filled in first: if the future is anything like the past, local issues unique to each site will mean that things pretty much get filled in semi-randomly. I once crossed through the U.S. early in the buildout of the Supercharger network, and had the closest call going from Las Vegas to Beaver, UT (about 400 km and uphill) - St George, UT was installed months later. Likewise, I was just one week early getting between Billings, MT and Rapid City, SD, having to stop at a hotel with a charger to charge overnight. (Which was actually not at all inconvenient). I expect we'll see a lot of those sorts of temporary gaps as the Canadian Trans-Canada segment is built out.