I became an expert though at wells and septic's and surveying.. to this day I can read a quad map aerials and other stuff most folks just stare at.. but now you have google earth its all right there.. 

The lender will use the appraiser market rent survey if vacant. 

They track cap rates across various markets and for different types of properties, but their service requires a subscription.CBRE Cap Rate Survey: CBRE regularly publishes a survey of cap rates across the United States, which can be very informative.