Here is how I would do it on my Garmin Montana:
1. Once at the track and ready to go, clear the current track on the GPS to start clean (Track Manager -> Current Track -> Clear Current Track).
2. Ride the track one time.
3. Save the current track and give it a name (Track Manager -> Current Track -> Save -> type desired name -> hit checkmark to save).
4. Plug the GPS into my laptop with a USB cord.
5. Launch Garmin Basecamp.
6. On the left column under Devices, Find the Montana, and click on the Internal Storage folder.
7. Now you should see the track you saved above. Click on it to view it on the map or right-click and copy it to any of your track lists.