The pilot reported that he saw, what appeared to be his intended landing runway and set up for landing. During the landing touchdown, the pilot noticed that the airplane was difficult to control due to the soft soil. As the airplane continued the rollout, it drifted about 20 ft off the pilot’s intended direction into softer soil. Just before the airplane came to a stop, the right tire sunk into the soft ground and the airplane nosed over coming to rest inverted. The airplane sustained substantial damage to the right-wing strut and vertical stabilizer. The pilot reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operations. After the accident, the pilot reported that he had not landed on his intended runway but on an unimproved dirt road about 0.3 miles from the runway that ran parallel to the runway. The pilot reported that he had spent too much time looking for traffic in the landing pattern and lost situational awareness of his position relative to the runway.