AFTER OVERLOADING THE AIRCRAFT WITH 5 PAX AND BAGGAGE, THE PILOT DEPARTED ON A PERSONAL CROSS COUNTRY FLIGHT TO PHOENIX, AZ. HE CLIMBED THE ACFT TO AND MAINTAINED AN ALTITUDE OF 14,500 FEET MSL UNTIL REACHING SALT LAKE CITY, UT. THE AIRCRAFT WAS THEN DESCENDED TO AN ALTITUDE OF 7,500 FEET MSL AND LATER CLIMBED BACK TO 14,500 FEET MSL. WHEN THE AIRCRAFT WAS APPROXIMATELY 60 MILES NORTH OF PRESCOTT,AZ THE PILOT HAD EXTENDED HIS VFR FLIGHT PLAN BY 15 MINUTES. AFTER AN ACTUAL ENROUTE TIME OF 5 HOURS AND 27 MINUTES AND WHEN THE AIRCRAFT WAS ABOUT 20 MILES SOUTH OF PRESCOTT THE ENGINE FAILED AT 14,500 FEET. THE AIRCRAFT STRUCK A TREE AND COLLIDED WITH THE GROUND IN AN ABANDONED CELLAR DURING THE NIGHT, OFF AIRPORT, FORCED LANDING. NO FUEL WAS FOUND IN THE AIRCRAFT'S FUEL SYSTEM AND NO FUEL LEAKAGE WAS NOTED AT THE ACCIDENT SITE.