Put in a guest shower if you want your guests to return.

Where are the guests using the shower sleeping?

Perhaps enlarge the "guest bath" to include the tub or shower- whichever you would use less. Move it out of the master and keep what you would use most often.

A pocket door would allow access without taking up much space. Obviously you can't have the pocket door walk into the actual shower, so that would need to be shorter to allow for a door. My parents custom built home has a master bath with two doors: one from the master bedroom and one from the hall. I'm not sure if it was to allow guest access or easier access for them, but it seems like a similar concept. Alternatively you could do a tub/shower combo in your master bathroom and take the extra space and make the second bathroom a full (or 3/4) bath with shower as well.

You didn't say your age or how long you plan to stay in this house, but even young people can have accidents and need crutches or a walker. If you are planning this as your "forever" home the interior stairs might not be the best design.

I just realized that the den is likely also a guest bedroom. I wonder, if you move the den to where the bathroom is, and shift the bath and bedroom to the left. so the bath is between the den and bedroom, the bath can be accessed from the hall only, perhaps the door tucked back a bit.

chispa - I often wonder about the European housing designs. One that stands out the most is the 3rd floor apartment (was actually on the 4th floor as they don't count the 1st floor) that we stayed in while visiting Amsterdam. We had a heck of a time getting our luggage up the stairs when there was no elevator in the building. I can not imagine what residents do when they get injured or break a leg! From then on, we made sure that we rented places that have access to an elevator. We don't mind doing the stairs, but carrying the luggage up and down is not fun.

František Škuta - You asked how to hide a door. There are many bookcase types of doors that open to reveal an opening. Invisible door

@nhb22 - Not relevant to OP's question, but there are loads of five story walkups in New York City. Under older housing laws, that was the maximum height without an elevator.

Older people do have it rough if they live on an upper floor without an elevator. Not sure how they manage but I would imagine many become recluses because getting out is physically challenging. Many of them are dying as they age but many of them had to live there because their units were either rent controlled or rent stabilized so they couldn't afford to move.

😯

Some comments are puzzling. Are people actually saying that if they visit someone who doesn't have all the amneties you have back home, you would not visit them again? If so, maybe it's for the best.

I have a huge home with more bathrooms than people. When I visit others, both here and in a different country, I will happily sleep on a sleeping back on the floor and share bathrooms. Most people do. You visit people because you want to spend time with them, not because they have a great guest bathroom.

Dobrý deň, František. Where do you live in Slovakia? I lived in Košice for 2 years and got to travel all over your beautiful country! I am looking forward to visiting again and bringing my husband and children (I was only 22-24 and single when I lived there)!

I know this might seem strange but I am curious if you could simply have your shower built so it can be accessed from both the wc and your master bath. A sliding glass door (perhaps you could use colored or smoked glass for more privacy) in the wc that could stay closed until you have visitors. If you have a curb/step on your shower access from wc that (along with the door) could help prevent most water from entering wc. Move the washing machine to where the toilet is as you have suggested and slide the shower down a bit into space where washing machine was, so access from both sides is better. Or if you can move the washing machine location out of bathroom (both my flats in Košice had washing machines in bathroom so I know its quite common) you could keep that second toilet, which could be nice.

Honestly based on OP's life style, I wouldn't worry about having a shower that can only be accessed through the master bedroom - unless she is worried about resale value.

In my experience hosting guests (and being a guest) in metropolitan areas, where a pull out sofa is the norm, having guests use the shower on such an occasional basis through the master bedroom isn't a huge big deal.

As long as one has an actual toilet so they don't have to creep into the bedroom in the middle of the night it is fine. Many people host guests (and live) with one ONE bathroom and manage to schedule showers so it would not be a huge inconvenience for the person to need to walk through the master bedroom to take a shower once a day.

The only time I ever felt weird was when the only toilet in the apartment was only accessible by walking into the master bedroom and so if one wanted to pee in the middle of the night when my host was sleeping, it felt awkward.

But again, it depends on lifestyle and also resale. I wouldn't buy a home that had a master only accessible through the master unless it was a coop or condo in a place like San Francisco, London or NYC where one makes all kinds of compromises unless one's budget is well over a million.

Instead of a hidden door, one that locks to keep random walk-ins out of the master bath should be fine. Visitors that try it and find it locked should be too ashamed of their nosiness to comment. :)

I think your plan is fine as it is. Guests have a toilet and sink to use anytime, and once a day if an overnight guest would like to shower it shouldn't be a big deal to coordinate with you to use your shower.

I don't get the need for a secret door. Why not just put in a door that locks?