THE ACFT DEPARTED SARATOGA SPRINGS, NY, EN ROUTE TO MANASSAS, VA. WX WAS VFR AND AS THE ACFT APPROACHED GAITHERSBURG, MD, AT 2132 LCL THE PLT CONTACTED DULLES APCH FOR VECTORS THROUGH THE AREA TO MANASSAS. THE ACFT WAS ISSUED A HEADING TO MANASSAS. SHORTLY THEREAFTER THE PLT REPORTED HAVING MANASSAS IN SIGHT. THE THE PLT THEN MADE A VISUAL APCH TO RWY 01 AT WOODBRIDGE APRT. ALTHOUGH A WITNESS REPORTED HEARING THE PLT MAKE RADIO CALLS THAT HE WAS ENTERING THE PATTERNAT MANASSAS, HE REPORTED NEVER SEEING AN ACFT IN THE MANASSAS TRAFFIC PATTERN. ACCORDING TO THE SURVIVING PASSENGER, THEPLT HAD TROUBLE GETTING THE RWY LIGHTS TO ACTIVATE AT THE ARPT (WOODBRIDGE) AND A GO-AROUND WAS ATTEMPTED. HE NEXT RECALLED SEEING TREES AND THE ACFT IMPACTING THE TREES. THE ACFT CONTACTED THE TERRAIN IN A NOSE DOWN ATTITUDE APRX 375 FT NORTH OF THE DEPARTURE END OF RWY 01 AT WOODBRIDGE ARPT. WOODBRIDGE HAS LOW INTENSITY RWY LIGHTS WHICH ARE ON FROM DUSK TO 0400Z. MANASSAS HAD RADIO OPERATED MEDIUM INTENSITY RWY LIGHTS.