How to get to Tower of Rot
To reach Tower of Rot you'll first need to travel to Dead Hills, another CoTF zone. For more information on how to get to Dead Hills follow the link provided. The door that we need to click on in Dead Hills to reach the Tower of Rot is in the western most portion of the zone.
Use my map above if you need some guidance in navigating Dead Hills. Note that where the path abrutly ends and then picks up on the other side of the gap, you'll have to click on the wooden walkway in this location. You'll be teleported to the other side.
Additionally the large constructs of rot that see through invis and scowl at you ready to attack - they have an extremely small agro radius and so long as you hug the walls you won't even agro them. In fact, I was able to run right through one and nothing happened!