Can't help with dimensions.
But the side bays look very similar to the side bays on the N7 cabooses.
Extras of these used to be included in the Walthers kits.
While researching information I came across pictures of a PC/CR N%K caboose awaiting scrapping. According to the Conrail caboose website these are modified ex ATSF cabooses. I want to build 1 or 2 for my layout. I will start with the Athearn ATSF caboose like they did. But I can't find any drawings or diagrams anywhere. Does anyone know the dimesions of the baywindown Penn Central added to the sides and exactly how much (height) of the cupuloa was left when cut down? I found drawings of Penn Central modified ex NH cabooses. They blanked the cupula anda dded baywindows to them. However the baywindows on the N8A and N8B seem to be taller than those of the N5Ks. Any information would be extremely helpful. Thanks