THE PILOT REPORTED HE WAS ATTEMPTING TO TAKEOFF FROM A REMOTE, UNIMPROVED LANDING SITE. HE STATED THAT HE HAD ABOUT 300 POUNDS OF DEER MEAT IN THE BACK OF THE AIRPLANE. HE STATED THAT HE WAS TIRED AND SHOULD HAVE SLEPT, BUT HE DECIDED TO TAKEOFF INSTEAD OF SPENDING THE NIGHT. DURING THE TAKEOFF ROLL, AS THE AIRPLANE BECAME LIGHT ON THE WHEELS, IT DRIFTED OFF THE RIGHT SIDE OF THE TAKEOFF AREA. ONE OF THE WHEELS HIT SOME BOULDERS AND SLOWED THE AIRPLANE. THE AIRPLANE THEN CONTINUED OFF THE RIGHT SIDE AND NOSED OVER IN BRUSH.