Did you try the Bathrooms forum? Or perhaps Home Decorating.

I am in the process of "updating" a master bathroom for a client and we removed the corner garden tub, capped off plumbing and replaced flooring to create a small area for a sit down vanity. We put wainscoting up around where the tub was to give it a nice finished touch. But, you MUST figure out what you can spend first. That will help you figure out what you can do. As a minimum, I would remove the tub, cap off plumbing and wainscot the area, then paint the vanity a color you like, replace the flooring to work together with color for vanity and paint the walls accordingly. Replace lighting for more light.

We IMO MCM bathrooms were not really all that great and cracked tile repair is iffy and honestly do you think the money spent to repair will be money well spent. Talk to your realtor , what sells in your area. I have a MCM ranch 1956 and two things I changed right away were the bathrooms and the kitchen( I even moved the kitchen) we don’t live in the 50s anymore and I don’t think redoing something to bring to a space into our century is a bad thing. I know so many on this forum want to stay true to the original, I want to enjoy my house for how I live.

What about a striped curtain. This is just an example. You'd need one with a beige or ivory and white stripe.