Tough problem. Aside from the Minnetonka chain and other metropolitan lakes there isn't a lot that close in that is not residential all around. Lakes in MN tend to run in clusters where the glaciers left the holes. Closest to metro might be Forest Lake or Big Marine Lake but not sure if there are places to stay on those.

For a more rural setting I think I would check around the Maple Lake area on Hwy 55. Maple Lake, Clearwater Lake, Cedar Lake, etc... may still have cabin places. A little farther would be the Glacial Lakes area between St. Cloud and Willmar..Rice lake, Lake Koronis, Green Lake. And a bit more (pushing 2hrs+) would be near Sauk Center...Sauk Lake and Big Birch Lake. All these might make good web search starting points.