WHILE EN ROUTE AT NIGHT ON AN IFR FLT PLAN, THE ACFT RAN OUT OF FUEL. SUBSEQUENTLY, THE PLT WAS PROVIDED VECTORS TOWARD A HIWAY FOR A FORCED LNDG. HOWEVER, BEFORE REACHING THE AREA OF THE HIWAY, THE ACFT CRASHED ON RISING TERRAIN AT AN ELEV OF ABOUT 4000 FT. EXCEPT FOR LACK OF FUEL, NO PREIMPACT ACFT OR ENG PROBLEM WAS FND. APRX 26 MI NNE, THE 1838 PST LAS VEGAS WX WAS IN PART: ESTIMATED 400 FT BROKEN, 1500 FT OVERCAST, VIS 4 MI WITH FOG & LGT RAIN. THE ELEV OF THE WX FACILITY WAS 2174 FT. AN INV REVEALED THE ACFT HAD BEEN FULLY SERVICED WITH FUEL ON 12/3/86 & HAD FLOWN APRX 4 HRS PRIOR TO THE ACDNT FLT. NO RECORD WAS FND OF ANY FURTHER REFUELING. THE ACFT HAD A FUEL CAPACITY OF 88 GAL, OF WHICH, 4 GAL WAS CONSIDERED AS UNUSABLE. ACCORDING TO AN ESTIMATE BASED ON FLT MANUAL INFO, THE ACFT WOULD HAVE CONSUMED NEARLY88 GAL OF FUEL SINCE THE LAST KNOWN REFUELING. ON 9/3/86, WHEN THE PLT TOOK A MED EXAM, HE RPRTD HE HAD A TOTAL FLT TIME OF 2930 HRS.