Your trip is close, fun!
Poly does have a gym, it shares a facility with the GF next door. It's a short walk over, a nice warm up actually. Your MagicBand will open the door. It's in the small, seperate building just past the Wedding Pavilion but before you get to the GF DVC building. The Senses Spa is in the same building.
I run outside on the path between the TTC/Poly/GF. Nice and flat, good scenery - it's a wonderful morning run! Usually there are quite a few early morning runners out, in my experience. I'll see if I can look up my running history on my watch to let you know the distance.
There are "New Balance" signs in a few spots that show an actual trail, but I will just wind my way around both GF and Poly and make my own path.
Hope that helps!