Althought it's not exactly about the Cour d'Alene region:
The excellent book Sternwheelers and Steam Tugs: An Illustrated History of the Canadian Pacific Railway's British Columbia Lake and River Service by Robert D. Turner covers the lake and river boats in the Kootenays and contains a huge number of pictures and drawings.
Since these northwest steamboats were of the same type on both sides of the border, it might be of some interest for you.