We've done that exact drive (well an extra 2.5hrs up from Lethbridge) in a Mazda 2 with a full load of five people.
Somebody wrote in to say that they'd done that route Tofino to Quebec and back in a Renault 8 towing a Boler. I don't think anyone's going to top that for most ambitious.
Anyway, the 4-speed and the hatchback shape hurts the highway fuel economy - this is more properly a city car, and it'd be really good at that job. The SR is a great fit for an older driver who just wants easy-to-park, low-headache transport, and it has pretty much everything you need.
The mid-range SV with an auto is 16K+ tax including freight, as compared to about 800 more for a Mirage SE. the structure reminds me of the previous-gen Versa, where the four-speed was the base option, or you could step up to the CVT in the higher models (and many did).
Right now, in this market, the financing on the Micra is what makes it a bit less competitive, unless you're leasing. Mazda2 has very aggressive rates as per usual for Mazda this time of year.