On our trip up last August we found almost no one took Discover in Canada. Used our Master Card quite a bit but seems in Canada they use the chipped card system making swipes a bit more cumbersome- but the swipes did work. This year I am going to add a VISA for our trip up to Anchorage and ask for replacement cards that are chipped. My AMEX card was just changed out to a chipped card and it worked in a few spots around Banff.
Did the trip in a TC last year so didn't need a lot of cash for "just in case" fueling. Think we got $200 CN once we got to Banff and only used about $20 cn for laundry. Arrived in Canada on a holiday so swapping cash in a bank was tough.
This year we are in our MH with a much larger tank and will have higher refueling costs so will get about $400 CN just in case to compliment Visa and MC.