Here is the University's Directions and Maps for traveling to the Ohio University Athens Campus from various directions. The Church of the Good Shepherd is located in the southeast corner of the main (old) campus (see 'home grown' map below).
This is an interactive Campus Map. The Church of the Good Shepherd coordinates are H - 4.5. On the specific College Green area map one can see the ghostly outline of Good Shephard in the lower left (next to the Konneker Alumni Center, #60).
Here is a home grown map showing specific directions to the Church of the Good Shepherd and other details.
For fun, here is a USGS aerial photo of the Church of the Good Shepherd, center (note cars behind), via Microsoft's Terraserver. Zoom out for a better view of Athens.