Actually the walk can be done in 5 minutes if you walk briskly. Also, to walk straight to the GCH of the Poly, veer left as soon as you can after you get on the short trail that goes to the Poly. That's a more direct route to the GCH. The trail you're on when you enter the Poly kind of winds around the resort a bit before heading to the Volcano pool/GCH area. I believe there are small signs directing you to go left to head to the GCH and straight to go to other places. Going left takes you nearer the front of the resort, where the GCH is. This is going from the TTC to the GCH of the Poly.
If walking to the TTC from the Poly, just try to find a path as close to the front of the resort as possible. That will generally lead you to the little cut through path to the TTC.