I'm sure your sister will have lots of ideas. The classics:
Batoche National Historic Site
Prince Albert National Park
Our favourite easy walk is the Boundary Bog with carnivorous plants. We also saw our first Escape in PANP, thanks!
Lots of good restaurants in Saskatoon. Some fun shopping and browsing streets on 20th and Broadway. River Cruise on Prairie Lily. Wanuskewin Heritage Park.
Handy people are the Karpans
Great Saskatchewan Bucket List is good book for exploring. If you can buy it before you get here, you can plot out some things. Or Sister could check out from library if she doesn't have it?
Parkland Publishing book: The Great Saskatchewan Bucket List by Robin and Arlene Karpan of Saskatchewan, Canada.