THE NON-INSTRUMENT RATED PILOT RECEIVED A WEATHER BRIEFING THAT INDICATED INSTRUMENT METEOROLOGICAL CONDITIONS (IMC) ALONG HIS ROUTE OF FLIGHT. THE AIRCRAFT COLLIDED WITH TERRAIN APPROXIMATELY 11.5 MILES SOUTH OF FRONT ROYAL, VIRGINIA, AT AN ELEVATION OF ABOUT 2400 FEET. NO PREIMPACT PART FAILURE OR MALFUNCTION OF THE AIRCRAFT WAS EVIDENT. THERE WERE NO WITNESSES TO THE CRASH; HOWEVER, AN AUDITORY WITNESS HEARD THE AIRCRAFT FLYING LOW OVER THE MOUNTAINS. THE WITNESS STATED THAT THE ENGINE WAS OPERATING, AND THAT SHE WAS UNABLE TO SEE THE AIRPLANE AS THE CLOUDS HAD OBSCURED THE MOUNTAINS.