This is a list of a couple of nice places to stop when driving out west on the transcanada:
Near gull lake, SK, there is a MeadowVale Golf course. Use their drive and make your way a 100m west (or so) to: https://goo.gl/maps/z3auo
Regina is tough. Best thing I have is the weirdly named "Dyer Straights Campground" a bit west at: https://goo.gl/maps/VMNfH
East of Winnipeg, just across ON border, is Whiteshell provincial park, a kind of mega campground: https://goo.gl/maps/Kqynl
Near Dryden (between Kenora and TB) is Aaron provincial park: https://goo.gl/maps/jC3rD
In Fort William (across from TB, to the SW) is Chippewa park, in the rez: https://goo.gl/maps/gT5PX
a few dozen km east of TB there is Sleeping giant park. Probably near 20 km off highway, so not super convenient: https://goo.gl/maps/XO4lX
At the very NW tip of Puksawa park there is a really nice provincial campground, Hattie Cove: https://goo.gl/maps/7QOKb
One of my faves is on Alona Bay, about 108 km N of the Sault. On the old highway. Turn towards the lake (W) from https://goo.gl/maps/rOsDQ and drive along the old highway for a few hundred meters to: https://goo.gl/maps/hYAua There are a couple of primo campsites along the old road that are very nice.