I would NOT mount any toilet paper holder or towel bar any place where it could be bumped hard because as we all know, the room is confining enough. You could easily rip it off the wall when trying to towel down, dress or undress. We keep the toilet paper in the sink cabinet.
We mounted a paper towel rack above the bathroom window, and a bath towel rack over the toilet which we store dry towels in and hang wet towels through. I think a retractible cord that you hook across the inside the shower when done will be a good addition for temporary towel drying. I have seen and used them on cruise ships and they work great.
We have a folding stool to sit down on when showering. We quickly got used to the shower stall and manage very well, sitting down most of the time. Sure more elbow room would be better, but it does work well for us. My wife is 5-1 and me 5-11.
I surely understand your delema with pots and pans. Those extra large cabinets we have over the fixed dinette is where that stuff goes, along with boxed and canned food. We would be lost without them. I hope you find a good working alternative.
If I had a slide-out, I would be tempted to remove the barrel chair and install a pantry cabinet like is commonly found in regular house kitchens. Someone with good carpentry skills could contour the cabinet walls to follow the wall curves of the coach, so it looks like the factory installed it. The cabinet could be modified to stick out as far as the cabinets above it. You should be able to order one that matches your other cabinetry from a home improvement store.
Phoenix USA might take care of it for you for a fee. They offer something today that goes there, but I think it is too shallow to hold all that. Here is theirs. Don't be fooled by the pictures. The forward side is maybe 5 inches deep due to the angle of the back wall there.
I've babbled on enough.