Coffee Creek is one of those gems and it's right in my own Northwest Indiana backyard.
The park is just off of I90 or a short skip south of I80/I94 so if you find yourself in need of a break while traveling through northwest Indiana I highly recommend that you stop and stretch your legs.
The park is large enough for a 30 minute walk through wildflowers and wildlife along a meandering creek. It is pet friendly; just be sure to have them leashed and clean up afterwards.
The best time of year for Coffee Creek is fall when the fields are covered in golden wildflowers but spring's flowers are beautiful and you just might see a fawn. My favorite time is the quiet of winter.