I've never visited Lake Winnebago but see that the Wind Power Shop is there at the south end. Might consider sailing up there over a weekend and bring along kids that have some wind surfing experience. Might stay there for 2 days.

Any suggestions on what to do in the area if it is NOT windy?

Is best sailing spot to just launch from park in front of Wind Power if it is windy?

Call Kevin at Wind Power. Problem solved. Wind or no wind.

Winnebago is a great sailing spot. Best launch is off of Windpower. The shop is actually just on the south-east shore so it is still good for straight south too.

Kevin does still own the shop, but it is managed by Ben Herdrich (so you may speak with Ben if you call the shop - he will take care of you). They are very family oriented and have many options to get everyone out on the water. Plus, the water is shallow so it is a great learning spot.

Home website: www.windpowerwindsurfing.com/

Weather (current and history - very slick! And a webcam): www.windpowerweather.com/

Facebook is updated frequently too: www.facebook.com/windpowerwindsurfing/

There are some good trails at Kiekhaefer Park www.fdl.com/details/todo/kiekhaefer-park/

Lots of bike and running along roads near town too with various amounts of hills. Light car traffic for the most part - some weekends there are now bikes than cars. Check Strava.

Columbia Park is another neat area about 10 miles north of Windpower. There is a pretty tall lookout tower there with great views, along with the Jim & Lindas restaurant.
www.fdl.com/details/todo/columbia-park/
www.fdl.com/details/todo/Columbia-Park-T...t-Harbor-Lighthouse/
www.jimandlindas.net/

There is also the Fondy Sports Park on the west side of town (owned and operated by wind & water sport enthusiasts), including a new water park facility that is very nice. fondysportspark.com/

Windpower also has light wind activities like SUP and kayak, and always good guys to hang around with.

Lastly, Sunset On The Water is a great place to hang out regardless of wind and weather - but most of us like it best after a good session www.sunsetonthewater.com/