There's not really running trails per se - just sidewalks (concrete) around the hotel, or you could probably skirt parking areas and run from one All-Star to the others depending on how far you like to jog. If you are really set on a fitness vacation, I'd consider Coronado which has a fairly quiet mile-long path around a like and a nature trail, plus a small gym for post-run stretch or massage. My advice is to stay off the roads around Disney - they are just too busy and with too many tourists unfamiliar with the layout to be safe for running or biking.