THE PLT WAS RETURNING AFTER A 2 WEEK VACATION TRIP TO ARIZONA. AT AN ENROUTE STOP THE PLT ORDERED THE ACFT FUELED TO PARTIAL TANK CAPACITY ON 1 SIDE & FULL ON THE OTHER. HE ALSO GOT A WX BRIEFING WHICH ADVISED AGAINST VFR FLT DUE TO CLOUDS, FOG & RAIN. THE PLT HAD AN INST RATING BUT WAS NOT CURRENT. THE PLT CONT ON TO THE DEST & FOUND WORSE WX CONDS THAN FORECAST. HE ASKED OAKLAND CENTER FOR AN APPROACH & WAS GIVEN HOLDING INSTRUCTIONS & TOLD TO EXPECT DELAYS DUE TO HEAVY IFR TRAFFIC. AT THAT TIME THE ACFT HAD ABOUT 1 HR & 30 MINS OF FUEL LEFT. THE PLT HELD FOR 47 MINS BEFORE AN APPROACH CLEARANCE WAS ISSUED. ON THE APPROACH THE PLT REPORTED THE VOR INBOUND BUT RADAR DATA SHOWED HE WAS OVER THE ARPT INSTEAD. THE PLT WAS 3 MILES PAST ARPT WHEN CONTROLLERS TOLD HIM HIS POSITION. PLT CLAIMED HE HAD A FIRE & HAD LOST HIS GYROS & ASKED FOR VECTORS TO ARPT. ACFT CRASHED WHILE MANEUVERING IN IFR COND. NO EVIDENCE OF FIRE OR GYRO FAILURE WAS FOUND.