Iowa, Cedar Rapids area

Start at the junction of I380 & J Avenue NE
Locate that which draws all the childern, and the sign that names
this place. Then follow the 'blue line' northward until you find a
place to cross that has been provided by nature (and its not the
stones! :D) When you reach the other side, continue forward, toward
the noise...
You'll have to figure it out from there.
Good luck.