My parents have done a few different things; they love running at WDW and usually do 1 to 2 hours a day every trip (like they do at home, just better scenery in Disney!). Feb 2, 2010 I joined them and we took the boat from Contemporary to Fort Wilderness, then ran from there to Wilderness Lodge via what I think was a horse trail, then on the edge of streets to TTC, path from it to Poly, along Poly's beach to GF, then went baha for a while on a grassy area heading toward MK. Doubled back around the grass, took a jog near GF by a canal, and finally ended back at GF. Total distance was about 4.7 miles IIRC, plus a little bit on paths in the Ft. Wilderness area before I started my watch/GPS! (oops) After the run we took the monorail back from GF. If you'd like to know what they did on other days I can ask.
However, if I understand your question correctly, you want a pedestrian/jogging trail the whole time. The only similar path I'm aware of though is the walkway to MK and it is pretty short (10 minute walk); there isn't a dedicated 'jogging trail' in the area. However, you could take the monorail to TTC then go on foot following the path I took from there...