Prior to attempting the landing the pilot carried out an aerial inspection of the strip. The aircraft touched down on a gravel road leading to the strip, however, the ground track of the aircraft was effected by a windrow along the side of the road and the pilot was unable to control the aircraft. The pilot applied power to carry out a go-around, but the right main wheel struck a car tyre, which was used to mark the strip threshold, causing the aircraft to veer to the left towards a fence. The pilot managed to manoeuvre the aircraft over the fence but it struck the ground, wingtip first, in an adjacent paddock. The majority of the surface of the strip within the boundry markers consisted of a four metre wide road and the pilot was apprehensive about its use. However, following the conduct of a circuit at the strip by the aircraft's owner, the pilot decided to use the strip as the passengers were waiting to depart for Geraldton. On the return flight the pilot was apprehensive about the landing, but decided not to divert to a nearby airfield because of the likelihood of the passengers experiencing subsequent transportation delays. To increase the landing distance available, the pilot decided to land short of the threshold marked by the tyres at the edge of the road. Once on the ground the pilot's view of the tyres was restricted by long grass.