The two Port Orleans resorts are some of the best for runners. The easy choice is the nice wide paved path between the two resorts, but there is much more.
There are several bridges you can cross over when you get down to POR. The sidewalks are nice and wide in the mansions section. When you get down to the AB area the paths seem more narrow and winding, but they are still fine for jogging if there is not too much other pedestrian traffic. I would even feel safe jogging around the perimeter road at POR if you need to get in a long run, but it would not be quite as scenic as running through the resorts.