THE PLT TOLD A FRIEND THAT HE WAS GOING TO CONDUCT A SIGHTSEEING FLT IN THE LOCAL AREA. RESIDENTS OF A SMALL TOWN 2 MILES FROM THE ACDT SITE SAID THE ACFT CIRCLED THE TOWN AT LOW ALT SEVERAL TIMES AT ABOUT THE TIME OF THE ACCIDENT. THERE WERE NO WITNESSES TO THE ACDT. THE SAR SATELITE PICKED UP THE ELT SIG AT 2125 AND THE WRECKAGE WAS FOUND BY A GROUND PARTY DURING THE NIGHT, AT 0150. A GLIDER PLT, WHO FLEW THRU THE AREA AT ABOUT THE TIME THE WITNESSES REPORTED SEEING THE ACFT, ALSO SAW AN ACFT MANEUVERING AT LOW ALT NEAR THE TOWN. HE SAID THE OUTSIDE AIR TEMP WAS 70 TO 75 DEG F AND THERE WERE DOWNDRAFTS, 500 TO 1,000 FPM IN THE AREA. THE DENSITY ALT AT THE ACDT SITE WAS CALCULATED TO BE ABOUT 11,000 FT AND THERE WERE 3 PERSONS ON BOARD THE ACFT. THE TERRAIN AT THE ACDT SITE IS ROUGH AND MOUNTAINOUS WITH SHARPLY RISING TERRAIN TO THE N,W, AND S. FOUR 5 GAL DRUMS WERE FOUND AT THE ACDT SITE AND A PLACARD FOR AUTO FUEL WAS FOUND ON THE PANEL. NO STC WAS ISSUED FOR THIS ACFT.