My DD just got over RSV a couple of weeks ago and it was pretty scary to watch, when she breathed her stomach would suck in. But we got a nublizer and used that and seemed she got better pretty quick.
As for the gowning up, it is a precaution because RSV is highly contagious and easily spreadable (I forget what my Ped. said but she said the virus can survive for a long period of time on surfaces). My mother was an RN and she said that she thinks that they gowned up for RSV when going into the room. It is more to protect the other patients then anything else. Because of the easy transmission and having other patients that the nurses see and deal with they don't want to pass along the virus. Especially to patients that are already sick with things. So to me only makes sense to gown up to protect the other patients.
My DD coughed and wheezed. The Ped said it affects the lungs the lower lobes. Therefore; the extra effort to breath (actually they breath that way to push out air) and the coughing to raise the mucus.