I feel for you Pancho. She's had one knee operation and has partially torn ligaments in the other, plus arthritis in one hip. Stairs are not her forte, but there's no way she would stay downstairs. Sometimes in the morning she will get up an hour later than the rest of us, I think it's because she knows she has to navigate the stairs.
So, update.
Last night it didn't take her too long to come upstairs. And this morning she walked right into the living room like nothing was wrong. Then an hour later, with everyone's breakfast bowls in hand, I was able to coax her back through "the room". The way she came through it was not directly across from doorway to doorway, but rather she hugged the walls so she wouldn't have to cross the middle of the room, looking at the middle the whole time, like some kind of monster was there. Weird, but better.
Oh, and her nails are fine and she's never had weather problems. She has no problem with the kitchen linoleum or the tile floors out at work. It's strictly that she doesn't like the look of that floor area now.
I've got a Persian type rug. Maybe I will bite the bullet and see if laying that out eases her fears. Until my youngest thinks it's a toy (lol).