I would rather prefer her marrying, but I am really against the common wish for Sansa to marry a beautiful young princeling. I just am. I think she is already beyond the point of only seeing the Outward beauty. So when she marries I want a guy that will make her happy, older or younger or anything. Just the guy that will make HER happy instead of the other way around. A shiny young prince -I do not wish that. AT ALL. This will be coming back to the beginning and .. I don't like it.

Lonely mistress - yes, also not my favourite scenario (this is why I said "squinting"), but at least I can see it happening without characters being untrue to themselves.

For Sandor a happy ending will be to kill Gregor. I have also seen many sansa/Sandor shippers expressing sort of an opinion that Sandor is all about Sansa. I don't think so. I think he is all about Gregor.