Ahh yes, KSGS is a nice airport. The A/D building has a ton of scale models and r/c airplanes in it. One hangar down is the CAF hangar with a B25, P51, and some other planes.
The gas pump has mogas available if you can run that stuff:
Flying along the Mississippi river could be kinda scenic. This is Lake Pepin about 20 miles southeast of KRGK. That point on the nearest left bank is marked on the sectional as Lake City.
Not too far away from KSGS is the narrow private air strip of Voyager Village. There is a golf course and restaurant on field.
About 120nm to the north is Duluth. The harbor area on the west side of the Aerial Lift Bridge could make a good day trip. Either stop in KDLH and get a crew car at Monaco Aviation or stop at KDYT and call a cab, or do what I do and ride a bike that you've brought along. At KSUW there is a restaurant on the field called The Upper Deck.
KDYT... it can get rather windy.
If you keep going north, you can follow the shore of Lake Superior, flyby Split Rock Lighthouse, and turn around to land at KTWM, get the crew car, and goto Betty's Pies for lunch and pie. You'll want to call ahead to inquire about the crew car though as it is not obvious... KTWM also generally has the cheapest gas in the area.