Map route (in bold, bright green) from Springfield to Rockbridge, Missouri. This is a good one if you've got a driver's car and are not afraid of a few curves.
Go south from Springfield and pick up Missouri 14 in Nixa or Ozark. (Alternately, you could go east from Springfield to 125, then south to Sparta.)
Just past Sparta keep right on MO 125 to Oldfield.
At Oldfield watch for a left on T, and hang on tight, cause it gets a bit twisted!
County road T eventually intersects 76, where you want to keep left (East) towards Ava.
Just south of Ava turn right (South) on 5, which is pretty boring to drive after the excitement of T and 76.
Continue SE on 5 through Squires, and watch for a left turn on N, a nice twisty ridge road. When you drop off the ridge, slow down a bit - the turn to the Rockbridge Rainbow Trout Ranch (on right) is at the bottom of the hill in a sweeping curve, and is easy to miss.