Hi Christine:
There are a number of bus stops sprinkled throughout
Caribbean Beach Resort. According to the unofficial site, disneycaribbeanbeach.com, which has a several article on Caribbean Beach Resort transportation you may want to check out, bus stops are located at:
Old Port Royale Centertown
Trinidad North: by building 33
Trinidad South: by building 36
Jamaica: by building 46
Aruba: by building 56
Custom House
Barbados: by building 13
Martinique: by building 23
While subject to change, the first bus stop usually is either Martinique or Jamaica, depending on the bus.
Enjoy your vacation.