If you refer to my earlier post, ranking the trails at the deluxe and DVC resorts, you will see that I have the Contemporary Resort and Bay Lake Tower near the bottom. Running at the Contemporary is still a good experience. We own DVC points at the Bay Lake Tower and stay there more than any other resort due to its location next to Magic Kingdom. I never have a problem getting good runs there.
There are two paths from which to choose or you can combine the two. The first option is to follow the path from Contemporary that leads to and beyond the Magic Kingdom. The second is following the dumbbell shaped loop at the resorts. Maps are available at guest services in the lobby.
The Magic Kingdom path is a flat, 1.25 mile out and back. It starts on the path between the Contemporary and Bay Lake Tower, follows under the monorail in front of Tomorrowland to the entry to the park, then along the Seven Seas Lagoon till it dead ends at a canal. If you are doing a leisurely run or walk and do not care about slowing down or stopping, then it is a good route. If you are hoping to keep a constant pace, then you have to run very early. About an hour before the parks open, the path gets very busy. The congestion decreases after the park opens, but is still significant for the entire day. Once you pass the entry to Magic Kingdom, it is usually clear. There is also no shade along the entire path. The views are nice though. Space Mountain, Astro-Orbiter, Cinderella Castle, and the Train Station are clearly seen along the way. There are also good views of the Grand Floridian, Polynesian, and Contemporary resorts. The main area of caution, other than running over other people, is crossing the road across from Space Mountain.
The resort loop is 0.9 miles and is also flat. There are markers to help guide you. The path is rarely crowded. There are a few places that require caution, though. There is a supply loading area at the far end of Bay Lake Tower that you cross. You also cross the drop off area in front of Bay Lake Tower and have to watch for cars. Passing between the South Garden Wing and the Contemporary Tower is very tight and quite busy with people passing from one to the other. If you do not pay close attention, you can crash into someone. The scenery is not bad. The landscaping at the back of Bay Lake Tower, with tall bamboo shoots is attractive. The outer side of the South Garden Wing offers nice views of the canal and of Bay Lake, with boats and birds. You have a great look at the resort, the pool and the metal Mickey head behind the Contemporary Tower. You can access a water fountain by the restrooms of the Bay Lake Tower Pool, just a few steps off the path. Unfortunately, there is little shade along the entirety of this route either.
Pros: Great resort access to Magic Kingdom.
Nice views of Magic Kingdom and of Bay Lake.
Cons: Little to no shade.
The Magic Kingdom path is very crowded at all but very early times.
You have to pay attention for cars and others at several places.
Overall: Not bad. Best for early morning as you can run both routes and will not need shade. I recommend that you not listen music on either route as you really need to pay attention for safety.
Bonus: With a little extra time and effort, there are two other great options available from the resort. If you do not mind riding the monorail while wearing running garb and being sweaty (at least two of the trains smell like zoo animals anyway), then you can ride it to either the Grand Floridian or Polynesian and back and give those trails a try. (It has been done before.) There is also a ferry boat the also crosses over to Wilderness Lodge, where you can run its trail. The ferry is very slow, though.