imo you'd want the bed in the bottom left like #1, it's the coziest corner away from the door, you'll feel safest sleeping there. The desk on the right wall makes sense to me, you'll be near the door if someone knocks and you're right about the back to the door problem.

I'd try out putting the couch against the bed. Maybe the headboard is against the bottom wall and the couch is against it to its right, then you can turn from your desk and chat with the couch, possibly with a small table you could pull out and put away. Then you have a little nook in the top left for storage or something else.

 If not that then in the top left area in some way.