Okay, here's a simple lofting tutorial -anyone can make cool tracks in MAX- editing guide:

1. Start by finding a very good map of the track you want to create or simply draw one yourself
2. Gather as much data of the elevations you can get. It is very hard to correct any mistakes you make in elevations afterwards!
3. Fire up 3ds MAX
4. Draw the layout as a simple line. use "smooth" type and use as few vertices as is possible to avoid complex curves;

5. You can finetune the line by selecting a vert, click right mouse and select "bezier". Now you can use the handles to control the curvature;
6. Position the vertices along the z-axis to create the elevations. You can also rotate the handles to control the curvature in the z-plane;
7. Create a shape from a simple "corner" type line. This will be the cross-section of your track. In the example there is one segment for the road (vertices are highlited), the others are for the inner-grass, walls, outer-grass and fences. You might want to extend even more segments for grass outside the fence.
IMPORTANT: give each segment a different material ID ! We'll use this later on. You can give some segments the same material ID if the are oriented the same (wall sides etc).

8. Select the layout line and choose "compound objects"-> "loft"

9. Select "Get Shape" and click on the shape you just created. Voila, You will already see a 3d trackshape appear.

However, there are some things to adjust:
10. Open the "Skin parameters" rollout
11. Enter "0" for Shape Steps.
12. Increase "Path Steps" until you have smooth corners everywhere. This will determine your eventual polycount, so choose wisely! Check in 3d as well, since it may look smooth in the editor, but in the game the corners can look very crude. You will now have something similar like this:


There are some interesting parameters in the rollouts to toy with however:

-Contour: must be turned on
-Banking: Usually turned off, we'll use other ways to create banking
-Constant cross section: what it says...
-Flip normals: Sometimes the faces on the track are inverted

13. Adding banking and stuff. In the "Path parameters" rollout choose "path steps". You will see a yellow dot on the track which is the position of your current shape (A loft is a whole lot of shapes/cross sections tied together). With the up and down button you can navigate the dot along the track.
Select a shape and select "Get Shape" again and click on the original shape you used. You will see the shape appear in the place where the yellow dot is (when you're editing that is, otherwise it's invisble).
Move the yellow dot some distance from the point where you added the "new shape" and select "Get Shape" again and click on the original shape. When all is well, no changes where made to the track. You just defined two extra shapes in the loft, but since they are the same as the original nothing happens.
Now comes the fun part: Select one of the "new" shapes: In the modifier menu choose "shape" as sub-object.

Now select a shape by clicking or using the selection box (somehow I can't see them when they are not selected). It is now possible to Scale or Rotate that shape and you will see that the loft will change:

View while editing the shape:

View after editing:

14. You can now apply a material to the loft and work on the uv mapping:

In the "surface parameters" rollout select "Generate material ID's", "Use Shape ID's" and "Apply mapping". Now change "length repeat" and "width repeat" to get some sort of presentable mapping on your track. If you have used a material with multiple textures/material ID's you'll get the idea...
The UV mapping isn't finished, but because you gave each segment a different material ID it's very easy to select the faces (once it's a mesh) you want by using "Select by ID".

To get the track in the game you have to collapse the loft to a mesh (make a copy first) and cut the track up in parts. Use big parts for initial testing and keep the original layout line/shape and loft! That way you can always change parts later on.

The actual exporting to MTS etc. is already coverd in other tutorials....