I my experience the most common criteria to look out for when choosing a site are 1. Is it in a historical / archaeological area 2. Are the sightlines to the road achievable to the NRA guidelines, (if not will I be able to take back a ditch / fence to achieve these, sometimes this may be bounding neighbours land in which case we will need a letter of consent from the owner). 3. Will the soil be good enough to pass EPA test for septic tank or treatment unit. 4. Is the land zoned for something different, 5. Is there A LOCAL NEEDS CLAUSE ATTACHED TO THE AREA.