... not very, as you would expect from a trail that follows an old rail line.
Below you'll find the elevation chart for the developed portion of the trail.
The highest points, between Leeton/Chilhowee and between Greenwood/Lees Summit,
have an elevation of around 1,000 feet above sea level.
The lowest point, between Chilhowee/Medford, has an elevation of around 800 feet.
That difference of 200 feet is spread over many miles,
you can expect to not even notice the change.