I’m still in shock that 35 year old plumbing meeds to be replaced. Mine is 85 years old and working fine. Sorry you’ve got this problem.

Include in the comments a simple sketch of each bathroom including all measurements and you will get much better feedback.

If I were redoing this bathroom, I’d get the shower controls away from the toilet. It is quite a reach to get around the toilet to adjust the shower controls.

sounds like a great plan, just opening up the space and keeping the room light will be great. keep all the plumbing in the same locations will help on expenses, finishes simple and light.

A pony wall makes a lot of sense. Found this photo with an angled entrance to shower I think would work for accessing plumbing easier on the back wall. Imagine the wall to the left of the toilet is even with the left side of the window! The room is just about that narrow! Ignore colors etc. I really like the vanity sent by Kandrewspa.

I can very well imagine because I just finished remodeling a bathroom just that narrow too! (Our window was centered half above the toilet and half above the tub which made it impossible to build a glass wall. We had to go with a tub shower combo instead. Bummer.)

The angled entry makes sense, though you'd have to measure it out in your space. How much room do you have for your shower, width, and if you angled the entry, would the pony wall and vanity depth could end up being more shallow than a common vanity? Your inspiration pic looks wider than your actual bath.

Still, the pony wall makes sense per @kandrewspa. And if you have to walk in to a non-angled shower to turn it on, so be it.

Can't comment usefully without a dimensioned floor plan.

Draw and measure both. Every single inch noted, including the 4 inches between vanity and bathing and door size.

Upload as a jpeg in a comment below.