Attaching a ring-like handle to a castle door I'd like to attach a round metal looking handle to a castle door such as this one.

I did a search for 'ring' on Bricklink and found the life preserver.

Would this work, or are there better options?
I wonder if I could just thread a key ring through a technic brick.
I agree with Alex. There's no reason to settle for a ring, when you could use the ring.

Here's one way to attach it if you want the ring to look like it is hanging down from the door: