The pilot stated that he departed on the flight for the purpose of meeting with realtors. The meeting concerned a parcel of land. The pilot said he was circling the land at 500 to 700 ft AGL when he experienced a complete loss of power and attempted a forced landing in the field that he was circling. He stated it became apparent that the aircraft would strike trees during the roll out, if he continued, so he attempted to fly over the trees and land on a road which was beyond. A ground witness observed the aircraft circling when it suddenly lost altitude. He stated the aircraft came within a few feet of the surface when he heard a loud surge of power and then the aircraft flew through a row of trees. A passenger reported hearing the engine sputter and said they tried to land on a road, but could not stop in time to avoid trees, so took off again. The aircraft came to rest inverted on a road about 1/4 mile from the trees. An examination revealed no preimpact malfunction. The prop blades had extensive cordwise scratches.