WHILE EN ROUTE, THE PLT WAS PROGRESSING NORTHBOUND WHEN HE CONTACTED THE WASHINGTON FSS AT 2134 EST FOR UPDATED WX INFO. AT THAT TIME, HE DESCRIBED HIS POSITION AS NORTH OF LYNCHBURG, VA. THE FSS BRIEFER NOTED THAT HIS VOICE WAS NORMAL, HIS MANNER WAS CALM & PROFESSIONAL & THERE WAS NO HINT OF ANYTHING UNUSUAL. ABOUT 8 MINUTES LATER, THE ACFT HIT TREES & TERRAIN ON A SADDLE BETWEEN 2 MOUNTAIN PEAKS, ON THE APPALACHIAN TRAIL. INITIAL IMPACT OCCURRED IN LEVEL FLT ON A HEADING OF 190 DEG. AN EXAM OF THE WRECKAGE REVEALED NO EVIDENCE OF A PREIMPACT/MECHANICAL FAILURE OR MALFUNCTION. RADAR DATA SHOWED A PROBABLE TRACK FOR THE ACFT. THE TRACK PROGRESSED NORTHBOUND (354 DEG) AT 4400 TO 4500 FT MSL UNTIL PASSING ABEAM MONTEBELLO VOR AT APRX 2138:30 EST, JUST AFTER THE PLT ENDED HIS RADIO CALL TO THE FSS. THE ACFT THEN TURNED RIGHT TO ABOUT 170 DEG & DESCENDED TO 3700 & SLOWED FROM 180 KTS TO 138 KTS. AFTER FLYING NEAROR OVER THE WINTERGREEN SKI AREA, WHERE NIGHT SKIING WAS IN PROGRESS, THE ACFT CRASHED AT AN ELEVATION OF APROX 3700 FT.