THE PILOT HAD DEPARTED THE 1ST STOP OF A TWO STOP CROSS COUNTRY FLIGHT. SHE DISCOVERED AFTER ABOUT 30 MINUTES THAT SHE WAS OFF COURSE. COURSE DEVIATIONS WERE MADE LOOKING FOR A RECOGNIZABLE LANDMARK, WITHOUT SUCCESS. A GRASS STRIP WAS LOCATED WITH TWO TRAILERS. AFTER LANDING, NO ONE WAS LOCATED IN THE TRAILERS. A PASSING TRUCK DRIVER, ON A NEARBY HIGHWAY, WAS STOPPED TO ASK DIRECTIONS. SHE TOOK OFF AGAIN BUT WAS STILL UNABLE TO LOCATE LANDMARKS SHE KNEW. ASSISTANCE WAS THEN REQUESTED FROM CHARLOTTE TOWER, WHO VECTORED HER TOWARD SALISBURY. SHE ENTERED THE LANDING PATTERN AT SALISBURY, MANEUVERING TO AVOID ANOTHER AIRPLANE IN THE PATTERN. AS THE AIRPLANE WAS TURNED ONTO THE BASE LEG, POWER WAS ADDED TO SLOW THE DESCENT RATE & THE ENGINE QUIT. A FORCED LANDING WAS MADE IN A FIELD. THE AIRPLANE HIT A DIRT BERM DURING THE LANDING ROLL.