Preferred buildings in Alli Bayou are 14,15,18,27 and I am certain that is due to the proximity to the Main building and pool area (and Pina Coladas apparently
). They are more expensive but I can't remember (is it $25 per day?).
Honestly, I don't think the preferred rooms of AB are worth it (and neither are the "water views"). The preferred buildings are closer to the main building (and the SOuth Depot...main bus stop). But, as you said, that is also the busiest bus stop.
There are some buildings that are quite a distance from the main pool area but they are also close to a quiet pool and bus stops. We used to always ask for building 14, 15 or 18 but we have learned we actually like the peaceful quiet of the back buildings (27, 17...). It is hard to get a building that is close to the main pool and close to bus stops (hence, the four preferred buildings).
But, if proximity to the Pina Coladas is what you want, I would request building 39 or 26 (which are close but not "preferred") or just go with the preferred and pay the additional fee.
Enjoy! Hope you get one of the rooms with Queen beds (I think some of them have this feature...)