Saw this posted early few days ago. this is the latest schedule for buses from SS:
The schedule is as follows:
Shuttle departing from hotel to Animal Kingdom:
7:50am
9:55am
12:10pm
Returns to hotel:
2:30pm
6:20pm
Shuttle departing from hotel to EPCOT:
8:55am
11:05am
1:35pm
3:25pm
4:35pm
Returns to hotel:
4:00pm
5:15pm
8:15pm
10:10pm
Shuttle departing from hotel to MGM:
8:55am
11:05am
1:35pm
3:25pm
Returns to hotel:
4:15pm
8:00pm
9:25pm
11:10pm
When MGM closes at 8:00pm, last bus leaves at 9:25pm
When MGM closes at 9:00pm, last bus leaves at 11:10pm
When MGM closes at 10:00pm, last bus leaves 11:10pm
Shuttle departing from hotel to MAGIC KINGDOM:
7:50am
9:55am
12:10pm
3:25pm
4:35pm
Returns to hotel:
2:15pm
3:45pm
5:00pm
6:35pm
When Magic Kingdom closes at 5:00pm, last bus leaves at 6:35pm
closes 6:00pm, last bus 8:30pm
closes 7:00pm, last bus 8:30pm (same as above)
closes 8:00pm, last bus 9:35pm
closes 9:00pm, last bus 11:00pm
closes 10:00, 11:00, or midnight, last bus 12:40am
Shuttle departing from hotel to DOWNTOWN DISNEY:
(BY RESERVATION ONLY dial 1063 for reservations)
12:15pm
5:00pm
8:00pm
Returns to hotel:
5:15pm
8:15pm
12:30am
IMPORTANT NOTE: PLEASE MEET YOUR BUS IN LANE #32 AT ALL OF THE PARKS.
The bus to Magic Kingdom also stops at Animal Kingdom and then EPCOT. Bus also stops at MGM so please plan your schedule accordingly. For information or to make reservations for the Downtown Disney shuttle please call extension 1063 from your room or 407-239-4342 from outside the hotel. For wheelchair accessible vehicles please call the same numbers as above 24 hours in advance. Final return busses may arrive or leave late due to heavy traffic. For any transportation needs, concerns, or emergencies please call Bethany Transportation at 407-239-4342.
Here is a good write up about SS I found earlier :
http://www.wvnh.net/sheraton/sheratonsafari.htm