Ours is 4x7 with no door. The seat takes up 1' of that space. We lost the battle with the builder on the curbless entry. We very rarely have splash out issues even at the pony wall. A wheel chair can be pushed in for showering and then backed out. A handheld shower is a must for someone in a wheel chair or needing to sit on a bench/stool. My parents have an ADA compliant shower sized 5x6 with curbless entry and 4' wide doorway without a door. Splash out is not an issue for them either. Many people ask if its drafty or cold without a door and the answer is no. Basically when you have a curtain or door in place it blocks the flow of the hotter air caused by the hot water and keeps it in the enclosed space. When you then open the curtain/door you get cold because the air outside the enclosure is colder than the hot air inside the enclosure. When you don't have a door at all the entire room heats up vs just the showering enclosure, so there is no rapid temperature change experienced by your skin giving you that drafty/cold feeling. Hope this helps!

I had a room that size, probably smaller, as child in two different homes. Cannot remember that they were small to me personally. I spent a lot of time outdoors playing and activities inside the rest of the house. If you have plenty of room throughout the rest of your home for toys and play, in my mind it would be functional. There are so many storage options for beds with under storage, putting dressers in closets and using lights and storage on walls. Being creative in a small room can be great fun. As a nursery it would be fine, enough room for essential furniture. A full size bed is approx. 54 X 72. You might want to lay tape over a rug or floor and imagine the options from there and also lay out furniture if you already have some. If I were a guest in the small room, it wouldn't be a complaint from me. Someone posted a wonderful loft that barely fit a full size bed. Used for guests and a cozy reading area. The area was really well done. Check out Apartment Therapy if you haven't done so. Also Pinterest. I linked a search for you there. Click on Images and a ton will show up. Have fun doing this. It can be done. Here is a link that might be useful: Pinterest tiny bedroom search

I have a 24 inch door leading to my powder room on the first floor. Its never really been a problem, but I wish it was wider. Not sure why it was only 24 inches except maybe to prevent the open door from hitting the vanity.

No pictures or floor plan posted