AFTER LANDING ON A PRIVATE ARPT THAT WAS CLOSED TO PUBLIC USE, THE PLT WAS PROHIBITED FROM USING IT TO TAKEOFF AGAIN. HE RECEIVED PERMISSION FROM THE OWNER OF A GRAVEL PLT TO USE HIS 'HAUL ROAD' WHICH WAS LOCATED NEXT TO THE ARPT. THE ELEVATION OF THE ROAD WAS ABOUT 9400 FT. THE PLT TAXIED OFF THE ARPT & ONTO THE GRAVEL PLT ROAD. HE STATED THAT DURING THE TAKEOFF ROLL, HE LOWERED THE TAIL AS HE APPROACHED LIFT-OFF SPEED. AT THAT TIME, THE ACFT HIT A ROLLING DIP IN THE ROAD & LIFTED OFF TO ABOUT 15 TO 20 FT AGL & ROLLED THE ACFT INTO A SHALLOW RIGHT TURN. ACCORDING TO THE PLT, HE EXPERIENCED A POWER LOSS AT THAT TIME. HE LEVELED THE WINGS AND APPLIED FULL FLAPS IN AN ATTEMPT TO CONTINUE FLYING. REPORTEDLY, THE ACFT THEN HIT ON ITS NOSE & SPUN 270 DEG TO THE LEFT. AN EXAM REVEALED THE CARB HEAT WAS ON & THE MIXTURE WAAS AT FULL RICH, BUT NO EVIDENCE OF A PREIMPACT MALFUNCTION WAS FOUND. THE DENSITY ALT WAS ESTIMATED TO BE ABOUT 10,500 FT.