I live in the prairies.
About 500m from the Trans Canada Highway.
Its nearly all double lane from Winnipeg to Calgary now and in VG condition.
In Saskatchewan you will be riding this highway as there really is little else in very good condition. However if you wanted to tour a bit south and see the grasslands parks and buffalo jumps the roads are in good shape there as well.
I get to talk to a lot of europeans on bike tours as I live near to a campground about 10k outside of Regina.
The only negative comment I have heard on a regular basis in the never ending prairie winds which are either in your face or on your back.
I've ridden the trans Canada to Banff a few times now. Its the fastest way but the traffic gets heavy as you near Calgary.