Pamela,
In my OPINION, The orignal bathroom in the 70's vintage 4500's was a waste of space. A flimsy bi fold door, no shower, and too big. The new 4500 from
Trillium RV has a much better plan, once again, my opinion.
To retro fit such a bathroom on a 4500, (which I plan to do to one of my 4500's) would be quite a bit of work. I plan to glass over the front window and put on a small port hole. I will probably also remove the flat spot that the window sits in. I will follow the rounded curve of the front of the trailer. This way showers would be more private, and slightly more roomy. I am not sure if I will put in a sink, since one is in the kitchen, just outside the door. I will leave room for a good sized cupboard by the front door.
This trailer is good with the front dinette. You can leave the bed as a bed and still have someplace to eat. Good for a couple. I really like how Randy did not drill any holes in the shell to mount the table. Instead he ran a support on the wall, up from the floor. Just like how the factory does it.