Speedtroll,
We own a campground/cottage resort on West Lake and would love to accomodate you although we aren't in the northport area. You can check us out at
http://www.westlakewillows.com/cottagerentals.htm .
As for the north port area the only other cottage place I can think of is Baycrest lodge and marina
http://www.holidayjunction.com/canada/on/con0006.html on Big Island. I haven't been there but someone else might have that can give you some personal experience.
I know there are a couple other cottage places on Big Island but I don't know their names. Try calling the Prince Edward chamber of Tourism and Commerce. 1-800-640-4717
http://pecchamber.com/ they know everything
. Let me know if I can be of any further assistance.