Regarding the South Saskatchewan River portion from Outlook to The Forks (confluence with the North Saskatchewan, where the Saskatchewan River begins), is well-documented through a publication referred to as the EcoCanoe Guide. I might have a pdf saved somewhere, as it appears to have disappeared from the Meewasin web site. It's a great resource for those of us who paddle this stretch. Let me know if you want me to dig up a copy for you (certainly I have the hard-copy that I can scan if I can't find the pdf).
How long the Saskatchewan Rivers portion will take you depends on two highly variable factors: wind & waterflow. Peak flows usually hit Saskatoon by late June, but it really depends on the snow melt in the foothills of Alberta, and what they decide to release from the Gardiner Dam on Diefenbaker Lake. Lower flows = much more winding, trying to find a channel, and wading. That was the case all summer last year, the peak flows never came. By contrast, I think the North Saskatchewan, and therefore the Saskatchewan River as well, was moderately high?
Even with decent flows, the wind can be a major factor. Many inexperienced paddlers expect the river to be a leisurely float downriver. Sometimes, the wind has other things in mind.
Having said all of the above, 40km per day *should* be reasonable on the river portion, assuming you don't get several days of headwinds and the flows are at least moderate. You'll have to contend with Lake Diefenbaker and Codette Lake en route where there will be no current. Diefenbaker can keep paddlers wind-bound for a period since it's large and unprotected.
So, Zev, are you commuting to work this summer?

If this is the Zev that I think it is (we met at the whitewater festival, and I know your dad a bit), you have more experience in a canoe than most of us here, especially on large wind-swept lakes. I doubt you'll have too many troubles. Feel free to reach out when you pass through Saskatoon if you need anything.
Cheers,
Bryan Sarauer