Unfortunately, that workout trail course was laid out along the path to Wilderness Lodge - and that path has been closed for some time now - with new construction set to begin too, it's not going to reopen anytime soon. I don't even know if those 'stations' are still there but even if they are, you can't access them.
For walking/running/jogging, there's still tons of trails, paths, roads, etc throughout Fort Wilderness. You might see if you get lucky at Contemporary or Wilderness Lodge by going there hoping someone might let you in as they're entering - but you'd be taking your chances and might not get in. If you've got a car, there's a large 24hr gym on 192 about 6 miles from Disney that does day passes (Kissimmee Muscle).