According to the pilot, he arrived from the northeast and entered an extended right base for landing to the south at 1,700 feet msl (pattern altitude). The winds were reported as 3 knots from the south. Prior to being established on the base segment, he had input full flaps and lowered the landing gear. He said that by the time he turned onto final, the airplane "may have seemed slightly high, speed was good and descent rate appeared good." He landed the airplane on the first half of the runway, but that the airplane floated a little bit with the landing a little further than he had anticipated. The roll out was good until he reached a slight mound in the runway that created an optical illusion of the runway's end being closer than it was. He locked the brakes and skidded off the runway into the brush.