How big is the enclosure? Pics? I know that terrestrials will "pace" if the enclosure is too big. The recommendation is 3-4 times their size. If it's too big they say they get stressed. They "learn" their surroundings by feel and vibration. Even in the open wild Ts will only roam a short distance from their burrows. They basically wait for food to come to them. The only real exception to that would be mature males looking for mates. They might roam further. Then again, maybe your sling just hasn't found it's favorite spot yet..lol
The sling it self is about a inch and half leg span, and its just a simple glass honey jar, 6inch tall and 2 and a half wide. Shes mades loadsa hiding tube webs. Dont want to lose this sling bcos shes my only avic.