I am thinking of removing wallpaper in bath,what am I going to find underneath and can it be painted? There is a box of some sort behind the toilet,which is carpeted before I tear the carpet off, what am I going to find and can it be painted? Thank you.

Shadow,

In my 1985 Regency, the box located on the floor behind the toilet, is made of thin panel type wood. The box hides the water lines going across the floor.
I took the carpeting off the box and floor and replaced it with stick on vinyl tile. They were easy to cut and place on the box and floor.
Don't rely on the adhesive from the stick-on tiles. You may have to use some type of tile glue, very lightly, as some stick-on tiles will pop up from the heat.

Jim