There was a bit of miscommunication as I wanted a private room, but I was shown a shared room with another fellow traveler. I called the host to voice my complaint, and she promptly addressed the issue by giving me a private one bedroom.
Her parents live on the property, so don't be surprised to be greeted by them and their adorable grandson, who I didn't hear during the night, very well behaved it seems. On my last day, her mother even offered to cook me some fried rice, but I had to leave early.
I can't speak to the room that was originally listed, but my private room was pretty kick ass. The bed is like any other Korean bed, but big enough for an average sized dude from New York. It comes with a heater, which I never used.
The bathroom is pretty big and I don't remember having to compete with people for it. The host provides plenty of small hand towels which had no smell and can help you dry off even after a shower. There is a bathtub with no shower curtain, so be prepared for wet floors. The shower provides hot water and pretty good water pressure, although the hot water cut out sporadically, but wasn't too bad.
The key that's provided is really cool, as you just need to tap the locking mechanism to unlock the door, no need to fumble with a traditional key. The apartment is very close to the Seokchon metro stop, and very walkable to Jamsil station as well, which means you're very close to Lotte World and Seokchon Lake, with the Olympic Park a bit further out.
All in all, I loved my stay here, and would definitely stay here again the next time I visit Seoul!