¡Hola! from Las Cruces, New Mexico. Welcome to the Forum. Congrats! What a great find in a Trailer.
Wow! What a great Intro & Trip Report & Super Photos all in one.
We have a 16' Scamp as well, we found the toilet seat a little too high from the shower floor, and the 'rim' of the shower/toilet platform a little narrow and using it as a foot rest was going to cause a crack in it, therefore, I bought a small sheet of wood sub-flooring and cut a piece to fix over the shower floor. It rest on top of the rim around 3 sides of the shower. It covers the floor of the shower when it is not being used as a shower. It makes a very solid floor for the bathroom & for using the toilet. It does cut down on the head room, my wife can stand up, but I can not do so without bending my head to the side. I have not found this a problem. If I am in there, I am setting down. Keep the floor of the shower clean as well.
Removable floor over shower floor:
The factory left a fairly large piece of carpet over the installed carpet (to keep it clean, I assume) which I used to cover the new shower subfloor.
With your neat looking Oak interior, instead of carpet on the sub-flooring, oak would look great.
Keep your reports coming. Enjoy!