Old Key West has the following busses:
Magic Kingdom
Epcot
Disney-MGM Studios
Animal Kingdom/Blizzard Beach
Downtown Disney/Typhoon Lagoon
Character Breakfast busses start running at 7:00am. Theme park busses start running at 8:00am. Downtown busses start running one hour prior to Marketplace or Typhoon opening. (8:00-9:00)
Due to the typically low demand at Old Key West, busses typically run 13-17 minutes apart. Very seldom is an Old Key West bus crowded, however, during peak times, it is possible.
Theme Park busses go in this order:
Peninsular Road
South Pointe
Turtle Pond
Millers Road
Hospitality House
The Downtown Disney bus does the following:
Hospitality House (As Internal Resort Shuttle)
Millers Road (As DTD)
Peninsular
South Pointe
Turtle Pond
Hospitality House
This way, you can take any theme park bus to the Hospitality House, and then the Internal Resort Shuttle back to your room. (Just double check with the driver first, as sometimes the route may change for whatever reason.)