Illustration courtesy of Model Railroader Magazine.
This track plan from Model Railroad Planning 2011 shows the modeled part of the Stockton and Copperopolis. The Merced staging yard is just of the drawing at the upper right corner of the plan. Freeport staging is between Stockton and the Charleston area.
You can click directly on the plan for a larger view. To get the largest and clearest view, right-click on the plan and then left-click on "open in new tab."