You can also just model the track for example with blender or 3dsmax. Just create a terrain, then a road, project the road on the terrain, and you have a track. Create a tree, then crete a meshmap for the locations of the imposter trees, then use the meshmap for impostrs in 3drad, add som random translations to the imposters an you have made a wood. Same goes for other props. I think modeling the track gives you more controll now than btb.