This very rough sketch shows a concept from a house I stayed in. Very rough, so measurements would of course have to be made to suit code and best practices.

It makes the closet smaller, moves the sink and toilet to the right, and adds a pocket door between the powder room and a new room with a shower, and adds a door from that room into the bedroom. This allows the occupant to access the entire bathroom privately. When desired, the pocket door can be closed to hide the shower and the bath towel, robe, shower items, etc.

The bathroom as a whole could be more accessible by removing the closet and lengthening the bathroom into the little hall as much as needed. What is to the left of the office? Perhaps the closet could move there?

Why conceal the shower? Will it be unsightly?

You can install full height drapery panels to conceal the shower if necessary.

A powder room where you can see the shower or tub, no matter how pretty, is a bathroom. I like keeping the shower out of sight if this will also serve as a guest bedroom, or as a powder room when the guest is staying.

@bpath - Thank you! I love this suggestion! A door from the office is perfect! Are you suggesting

a wall with a door in between the powder room and shower? I’m fine with making the storage closet in the office smaller. I’ll post plans to show what is to the left of the office.

@BeverlyFLADeziner - Thank you for the images, they’re lovely! The shower will be pretty. I would just like a 'proper' powder room :)

Yes, the shower is in separated from the powder room, but if someone is staying in the office, they can leave the pocket door open for flow. So, kind of like those bathrooms that have the shower and toilet separated from the sink, but my idea makes more sense for a dual-purpose space like this. Maybe this picture is clearer, see the pocket door?

I'll be frank here, this seems like an oddity. I don't see how adding in wasted circulation space and another door within an "officially defined" Powder Room helps a guest psychologically to not see a shower when they choose to use the toilet. The second door will actually make them feel uncomfortable moreso than seeing a seldomly used shower. If a change had to be made, adding in a window to a bathroom would provide more happiness than not seeing a shower.

Space is at a premium here, and there are more pressing needs of this design, like the undersized Living Room and how the furniture layout conflicts with everything, or the Screened Porch and outdoor living that has hidden access down a hall.

I also think the living room is going to have much less useable space than you think based on the room dimensions.
Would you consider putting the TV in the cabinets to the left of the fireplace?
I can’t figure out how you will be able to come up with a good furniture arrangement that has the TV on the opposite wall from the fireplace in a room of that size.

There are plenty of issues going on here, but the question was about the guest bath. My experience first as a visitor, then as a houseguest, was that the separation of shower room from powder room was very nice, no matter which side of the door you were on.

If someone is to stay in that guest suite long-term, the bathroom should be lengthened to allow for more storage at the vanity, drawers below and counterspace, and recessed medicine cabinet on the side wall.

I notice there is no guest closet, but surely guests might arrive with a light jacket at least?

As to the rest of the house, the refrigerator should move to the same side as the sink. The tv and fireplace should be side-by-side; the room doesn’t appear to be long enough to allow for two seating areas, one by the fireplace and the other by the opposite tv. That would allow the bottom wall to be a bookcase wall, with a chair or two tucked in for quiet reading.

It would appear there is no backyard available on the lot.