If you can't enjoy nature at Fox Ridge, you're doing it wrong. There are oodles of scenic trails, some more challenging than others. Enjoy the water, enjoy the hills, have a picnic or play a game of baseball. You can't be bored if you can make it out there.
I absolutely love Lincoln Log Cabin any time of year. You can walk trails, see historical buildings, and mingle with the animals on the farm. Warm weather brings more frequent reenactments, but it's a beautiful location any time of year. It's perfect for planned or unplanned day trips.
This park is hidden, to be sure. Driving to it is a nice little road trip in itself, but the park is a real gem. There is an actual hidden spring which is quite beautiful, and there's plenty of hiking and exploring to do. I've been to every park in and around Charleston, IL, but this is one that I never knew about in my own backyard - and my dog loved it!