Yes, as I mentioned above, " The Joneses’ " would be correct.
The correct sign would say:
Bag End.
Tris
Someone correct me if I’m wrong, but shouldn’t this be Baggins’ and Jones’?
OK, Gollum, if my last name ended in “s” there’s no way I’d be putting that on a mailbox.
(Actually, my last name does end in “s”. For a housewarming gift, we once got something with the equivalent of The Baggins’. At lease it wasn’t the equivalent of The Baggin’s.)
For heaven’s sake, not “The Baggin’s”!
That’s the kind of thing that makes right-thinking people weep for hours.
You don’t have to. Just put “Baggins.”