I've not camped in the area, but based on the thread title,  here is my observation.

I've personally been dropped off or picked up by a tow operator (motor boat) running from Prairie Portage to Lincoln Island on three separate occasions.  I also observed a number of other motor craft in the area during transit.  So, if you are asking if the area is motor-free, the answer would be no.  However, they are supposed to operate in U.S. waters only (from my understanding).

dd