David J. Carter's book "POW Behind Canadian Barbed Wire" is subtitled "Alien, Refugee and Prisoner of War Camps in Canada, 1914-1920 and 1939-1946". There are lots of details on his site.
The book consists of 254 pages packed with information, plus 8 pages of glossy photos. The appendix has lists of the camps, a sample daily routine, a weekly list of rations for POWs, and more.
Among countless other stories, here are some excerpts from page 80 regarding an escape from the Angler POW camp:
Horst Liebeck and Karl Heinz Grund were both Luftwaffe pilots.... [They] reached a curve in the railway line where a freight train had to slow down and they climbed aboard....
There were still hoboes riding the rails and so the escapees didn't look completely out of the ordinary.
"By the time we reached Saskatchewan we realized people took us for tramps. We weren't even attempting to hide."
Five days after their escape, near Medicine Hat, Alberta their luck ran out, almost twelve hundred miles west of Angler.
(Wikipedia has an overview of the escape.)
You can order the book directly from Eagle Butte Press (in Canada but ships worldwide), or from Amazon -- including one seller in Montana that offers signed copies.