OK - here's what he said: He started from the Poly, since we were staying there, and ran over to Wilderness Lodge on the road that runs out in front of the Poly past the ticket and transportation center. He said if you want to avoid the highway to start at Wilderness Lodge. He said there is a very pretty trail over to Fort Wilderness campground along the lake and then, once at the campground, you can run in and around it (the cabins and camp sites) for a long time. He apologizes - he doesn't know the distances or anything. At the time, his goal was to run for 3 hours, so he did some looping. He said it was very pleasant. Around the campground people were driving golf carts to get around instead of cars, so traffic was minimal. I'm sure if you ask at WL they can show you where the trail starts.
Have fun!