Correct. There are two bus "lines" that run at CBR. One is a resort only line, that takes you from stop to stop within the resort. The other is the "external" line that takes you to the parks and Disney Springs.
My favorite sections are Aruba building 51 and Jamaica building 45, near the bridge. But, really, I'd take anything in those two sections without batting an eye. It's a quick walk over to Old Port Royale (the food court/main pool complex) and are frequently the first stops to drop off at night and the last stops to pick up when going to a park (which means that once you board the bus, you are pretty much on your way to the park, not having to wait as the bus circles the rest of the stops within the resort).