There is one cute little "hut" located near the jacuzzi that is near the two BFVS buildings. I have seen the maids clean it every day, so it is very clean. There are also restrooms towards the back of the Cabana Grill. The Palms restrooms are located at the foot of the stairs heading up to the Martini Bar and Lemongrass. None of the buildings are located very far away from the beach.
We have never had a problem just walking back to our room to wash up, or take care of business, for lunch or any other reason. Rooms at CSA are so close to the beach that it is no big deal. As noted above though, there are other facilities very close by as well. One of the reasons we love CSA is that everything is so close to the beach.