thelusiv is right, that's a big feature that needs to be added -- some way to select an object or objects and set the properties.
If you take a look at
this post, I have a huge list of steps for developing a track from scratch. Ideally, the steps should be something like:
* model the track in blender, then export it using the export script
* load the track editor, create a new track, add the objects, set object properties, trace the roadways, place starting positions, mark the timing sectors, save the track to your vdrift folder
* run the track in VDrift
Currently, the track editor can only trace roadways, place starting positions, and mark the timing sectors (and it's not a very elegant interface for doing those things).