Springbank and Red Deer both have restaurants at the airport, which helps eliminate ground transport needs if you're going to stop in Alberta.
Lac du Bonnet in Manitoba allows plane-side tenting if you're roughing it, and is right on a picturesque lake/seaplane base. Likewise, Kenora Ontario has some lovely lakeside accommodations and would be a short taxi ride to town.
In the Toronto area, Brampton is a good spot to stop for lunch. They have a little WWI aviation museum there with biplanes/triplanes you'll see out flying from time to time. Busy little airport, though I haven't been in years. In Quebec (again, haven't been for years) there is Les Cedre (Cedars) just west of Montreal, but it was getting a bit run down so probably want more current intel. It's a bit far away from downtown if you want to visit Montreal (recommended), so another very close option is St. Hubert, though they used to charge landing fees (not sure if they're still in place).
Also, make sure you check COPA's "Places to Fly" for good suggestions.
https://www.copanational.org/Placestofly.cfm
Have a great trip! Sounds fun!