Hi Kristi:
Buses are generally scheduled to depart every twenty minutes, give or take. Sometimes you won't have to wait long for a bus. On very few occasions, you may have to wait even longer.
There are a number of bus stops sprinkled throughout
Caribbean Beach Resort. I'm assuming you are asking which buildings within Caribbean Beach Resort may have transportation advantages. According to the unofficial site, disneycaribbeanbeach.com, which has several articles on Caribbean Beach Resort 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. You may want to call the Resort ((407) 934-3400) about a week before your visit to see if they can provide more insight on the bus schedule that will be in effect during your visit so you could determine if you should request a particular building.
Enjoy your vacation.