The MT portion of that isn't too bad -- it's decently traveled, though not very well serviced. Watch your mileage and preplan gas and hotel stops. There are some passes, and if the weather really turns, you won't want to be on them. The port at Sweetgrass is big but the last time we went through it had a sign that said it was not 24 hours.... check on that! And once into Canada, Lethbridge is a decent stop, with adequate food and hotels, and then a short drive into Calgary.