THE PLT HAD JUST PURCHASED THE ACFT & WAS FERRYING IT FROM ALLEGAN, MI, TO HIS HOME ARPT AT KANSAS CITY, MO. AN EN ROUTESTOP WAS MADE AT PEORIA, IL, WHERE HE REFUELED & CHECKED THE WX. AT PEORIA, FBO PSNL NOTED HE HAD FUEL ON THE SEAT OF HIS PANTS. HE SAID FUEL HAD GOTTEN ON HIS SEAT CUSHION FROM A LEAK AT THE TOP OF A FUEL SIGHT GAUGE (NEAR THE AFT SEAT).HE HAD THE ACFT REFUELED IN A LVL ATTITUDE (RATHER THAN THE USUAL NOSE LOW ATTITUDE) TO KEEP FUEL FROM LEAKING FROM THE GAUGE. BFR DEPG ON THE 2ND LEG OF THE FLT, THE PLT COMMENTED HE WOULD LIKE TO BEAT THE WX TO HIS HOME. DRG FLT, THE ACFTHIT A TREE, WHILE ON A NNW HDG NR MACON, MO, THEN CRASHED & BURNED. IT WAS FND ON 5/5/89. INV REVEALED THERE WAS A LOW CEILING IN THE AREA. APRX 24 MI NORTH AT KIRKSVILLE, MO, THE WX WAS IN PART: 500' OVC, 2 MI VIS WITH LIGHT RAIN & FOG. EXCEPT FOR THE RPRTD FUEL LEAK, NO EVIDENCE WAS FND OF A MECHANICAL MALFUNCTION OR FAILURE. BEFORE THE PLT LEFT ALLEGAN,HE HAD NO PREVIOUS FLT TIME IN THIS MAKE & MODEL OF ACFT & HAD NOT LOGGED ANY FLT TIME SINCE 8/10/88.