Each section of CSR has its own bus stop. The casitas stop is picked up and dropped off first when going to and from the parks (it is actually bus stop #2), then ranchos, then cabanas, then El Centro (the main building).
Casita 4 is closest to the casitas stop. Ranchos 6A is closest to the Ranchos stop (but far from everything else). Cabanas 8A and 8B are closest to the cabanas stop.
Here is the map to help you out:
Preferred buildings are casitas 1, 2 and 3. Cabana 9B will be business class in 2013. All others are standard buildings.
You can simply request "close to bus stop" unless you have a village preference. If you have strollers or wheelchairs, you might prefer the casitas since it is the first stop picked up.
Each village has a quiet pool. There are no rooms near the Dig Site pool.
If you haven't already made your request and your trip is next week (based on your ticker), you should go ahead and call in your request.