This is not going to happen at a small airport and without the collaboration of ATC: https://www.youtube.com/watch?v=OwbTq_4-jGg CAT3 landing need a lot of things aligned properly to work.
For a safe, commercial autoland you would need CAT3, but if you're willing to take risks you could get by with less. And you would need a friendly ATC anyway or you wouldn't stay hidden for long. But the fact that the plane is capable of landing by itself means that it could be somewhere other than the bottom of the ocean.