Evaluating different timber transport configurations for a large road network is a challenging task. Road curves are often too sharp to allow access to certain configurations. This paper evaluates the feasibility of using a geographical information system (GIS) road data set as a basis for determining the accessibility of plantation roads for several truck configurations and to determine the optimal road system for three given vehicle configurations by minimizing total cost. The main constraint considered is the ability of a vehicle configuration to move through the curves found in the road network of the Elandshoogte plantation, Mpumalanga, South Africa. There are two objectives in this project: 1) to evaluate the feasibility of using geographical information system (GIS) road data as a basis for determining the accessibility of plantation roads to several truck configurations and 2) to determine the optimal road system for the three given vehicle configuration by minimizing the total cost. Constraints are generated by calculating the amount of offtracking for each vehicle configuration for all the roads and road connections found on the plantation by using the OFFTRACK program (Erkert, 1989). The minimum cost network is solved by using NETWORK 2000 (Chung and Sessions, 2001).