THE PLT RECEIVED 2 WX BRIEFINGS BEFORE THE FLT & WAS ADVISED THAT VFR FLT WAS NOT RECOMMENDED. PRIOR TO DEPARTING, THE 50 GAL FUEL SYS WAS SERVICED WITH 35 GAL OF FUEL. THE PLT REPORTED THAT DURING THE FLT, HE DESCENDED THE ACFT THRU A HOLE IN THE CLOUDS ABOVE A HIGHWAY. HE THEN FOLLOWED ANOTHER HIGHWAY & TURNED TOWARD THE DESTINATION ARPT. WHILE UNDER A LOW CLOUD COVER, HE ENCUNTERED HALE & GROUND FOG, THEN BECAME DISORIENTED. HE THEN TRIED TO FIND THE HIGHWAY AGAIN TO LAND, BUT CRASHED INTO A HILL IN AN OPEN FIELD AT NIGHT. AN INVESTIGATION REVEALED THERE WAS .25 GAL OF FUEL IN THE LEFT FUEL TANK & 1.5 GAL OF FUEL IN THE RIGHT TANK. TWO LOCAL RESIDENTS STATED THAT THEY HEARD THE ACFT FLYING IN THE AREA FOR ABOUT 10 MIN PRIOR TO THE ACCIDENT. THEY REPORTED THAT THE ACFT MISSED THEIR HOUSE BY ABOUT 4 FT WHEN IT MADE THE LAST CIRCLE. THEY WATCHED IT GO OVER THEIR HOUSE, THEN HEARD IT CRASH INTO A HILL.