Caribbean Beach has two sides, and two entrances. Depending on the routing assignment of the bus, you may start on the A side or the B side. Currently, the Studios is tinkering with a "C" route.
"A" Route:
Martinique
Old Port Royale
Trinidad North
Trinidad South
Jamaica
Aruba
Barbados
"B" Route:
Jamaica
Aruba
Barbados
Martinique
Old Port Royale
Trinidad North
Trinidad South
"C" Route:
Trinidad South
Jamaica
Aruba
Barbados
Martinique
Old Port Royale
Trinidad North
MOD busses get dispatched from the Studios... to alternating routes... This is why you might see one bus right after another for the same park. Bus 1 started at Jamaica, and bus 2 started at Martinique... but because 2 got dispatched 5 mins later, 1 caught up to 2... so, 1 will be leaving CBR, but 2 still has to make the rest of the rounds. I know it sounds a bit confusing, but it all works out.
Times to the parks... CBR is in a central location... so I wouldn't worry about that at all. The longest trip might be to Animal Kingdom, and that's only because the bus stops at Blizzard Beach as well.