My husband grew up on Lake Winnie so we get up there a couple times a summer. The big draw up there is fishing. There are guide services at the various resorts. A couple years back, a storm knocked the power out at my in-laws place, so we camped at McArdles Resort on Lake Winnie. They don't have a campground as much as it's a grassy field with full hookups, so it's definitely nothing fancy, but the people there are wonderful. I know they have a guide service and charters.
There aren't many major touristy things to do in that area, however there are some nice towns to visit. Walker on Leech Lake is a nice little town with lots of shops. If you take Hwy 2 west to Bemidji, there are some fun things to do there. Paul Bunyan Animal Land has many animals and deer to feed if you're into that sort of thing. Bemidji has lots of nice shops, couple of very nice waterfront parks on Lake Bemidji, restaurants, etc. Be sure to visit Paul & Babe!
If you want a little farther drive, Itasca State Park is a nice day trip. It's a state park but has more of a national park feel to me. It has the headwaters of the Mississippi River, boat tours on the lake, a restaurant in the lodge, a couple of very nice visitor centers and many trails. There's also a scenic drive thru the wilderness area of the park.
You could also make a day trip to Park Rapids, a cute town with lots of shops that is south of Itasca S.P..
North of Park Rapids on Hwy. 71 is a place called Summerhill Farm, more shops but the best part is their little cafe, they have really good lunches there.
That's all I can think of right now but if I think of more I'll post again. Have a great trip and be sure to bring your bug spray ๐