I felt there were plenty of places to run when I stayed at As Mu. It was easy to run to ASsports and Music. I would pick either direction in the morning and round around the periphery of that resort. From there you can go out to the main road (Buena Vista Drive?) which has a sidewalk. FRom ASmovies you could actually run as far as the McDonald's. I did not try to run any further than the Mcdonald's, because it would involve crossing at intersections. I don't like the stress of avoiding cars when I am in an unfamiliar place.
I found the all star resorts a pretty fun place to run. All the buildings were very interesting. It was never really crowded early in the morning. I would say it was one of the more fun places to run (compated to POP, CBR, POR). SSR was probably the best for me.