ASmo is a great resort interms of layout. Did you physically book a Preferred room? Or did you book a standard room and request a preferred location? Preferred locations at ASmo are Toy Story, 101 Dalmations, and Fantasia; Standard are Herbie and Mighty Ducks. If your placed in Mighty Ducks, your actually closer to the main building and bus stops at ASmu but the walk to ASmo's main building is still a 3-5min walk depending on your walking speed!
As another poster mentioned, the All Stars do share buses; especially on return trips from Animal Kingdom and Blizzard Beach and Downtown Disney and Typhoon Lagoon. ASmo will be the last to be dropped off. For some reason return trips from DHS and Epcot vary but on our last trip, ASmo and ASpo shared a stop while ASmu had it's own. On a more recent trip, a friend mentioned ASmo having it's own stop at DHS while the other two shared :shrug:
Trying to get to the parks can vary but when we stayed at ASmu we only stopped at ASmo twice during the entire week before going to our destination. It seemed that Disney did it's best to "dedicate" buses to each All Star Resort.
I'd say that we expereince exceptional bus service and very minimal waits with exception to park closing. We waiting almost an hour trying to get back from MK EMH but it was mostly due to the time delay of loading ECV riders and the influx of riders. We never waited more than 15mins for a bus at ASmu and even when lines were long, bus were still coming and going, even double busing on some occassions.