I've scanned the judge's diagram of the track on which Bones earned his TDX , and touched it up with a bit of color, so you can get some idea of what a TDX track might include. The dotted lines are the cross-tracks. What is not so obvious is that this was a very hilly region, so the track went uphill and down. On the downhills, I had trouble keeping on my feet and often had to ask him to "whoa, wait" for a moment so I could follow him. Also the area had a lot of resident wildlife, including wild boar, deer, and cougar, so their scent was certainly present.
Bones earned his TDX on his very first attempt and he was track-sure every step of the way. Truly the epitome of a tracking dog.
To see his victory photo, taken in a wooded area similar to that of the last portion of the track, click on Bones TDX Victory photo.