Once you're North of Edmonton there's plenty of boondock opportunities, as well as many rustic government campgrounds with beautiful views.
Check out the Alaskan camping book from the Church's. They list a bunch of "formal" boondock sites. There's also informal ones, that may or may not be on the Internet.
Many websites and old posts refer to camping in gravel lots. When I drove through the Yukon, I found a locked gate across every gravel lot I came across.
Not much help for places in the states. I stayed in a parking lot in Whitefish Montana, it was next to a real estate agency downtown, sorry that's not much help.
