I would suggest you contact the folks up at Wishbone Resort on Cass Lake. The owners are originally from Cedar Rapids. The resort is above par for resorts in Minnesota. Their cabins are very well kept and clean and they have very good rental boats. They generally start their Fall rates the last week of August.
Cass Lake is very fishable as it has an island in the center of it that helps break-up the wind and waves so that you have very few "blow" days. You can also run over to Pike Bay or Lake Andrusia. Cass Lake has a very healthy Walleye, Yellow Perch and Musky population.
There is a newer Indian casino in Cass Lake, MN if you want to stretch your legs at night. Bemidji is a very short drive away if you need additional services, hospital, Target, Walmart, auto parts and repair shops. Also, you are a short drive from Walker, MN if you want to go to Reed's Sporting Goods or the other touristy attractions.