Hi,
I would avoid North Portal like the plague. Last time I went that route it took me 4 hours of waiting in line to cross. If you are willing to travel at 2 a.m. then the wait disappears.
If you are coming from Minot, use the port at Sherwood, ND. It is not 24 hours. There is a gas station at Sherwood--and I recommend filling to the gills at it. Fuel prices are considerably higher in Canada, and with the new carbon tax that starts on April 1, will be even higher.
The road from Regina to Edmonton is four lanes most of the way.
There are few rest stops. Many small towns have campgrounds. https://freecampsites.net/ is a good resource.
If you enjoy soaking in salty pools, consider adjusting the route to take in Manitou Beach near Watrous, SK.
I live in SK and may be able to offer much more detail about things to do or see.