Go to the draw tab and select the line tool, it doesnt have to be a polygon or arc. What youre doing is setting up the line type. Select the color, the style, and the width you are going to use. You should see the line style as you chose it in the Sample Line window.
Click the File
button then click the Import
button. Select the file type to txt. (IFyou want to import the T7 file, youll need to select the *.* type then look for the an1 file.)
Import the file of choice. In my case, Im opening NWT_WA_LINES - Motorized Trails.txt.
When the file is finished importing the map will zoom out to display all of the trails you imported in that file. The Draw file list will have a new addition of the file you imported, and you can rename this to suit your needs. Zooming in will allow you to see the details of the trails you imported.
You can only import one file at a time. GPX files can be imported in multiples. But again, size is an issue with T7.
I will update my website with these step by step instructions with screenshots when I have more time.
Now you may ask yourself how do you gain these text files besides my site?

M10B generously makes them available to me to translate and post on my site so some of the bandwidth burden is shared.
Life has been getting in the way recently so I'm a little behind. I will try to get caught up after this month's HOTM.
Edited to add: You can delete the file from the saved location once it is imported. As the copy is now in the Delorme Documents folder.