It will probably just end. Oda has said many times that he planned out the ending years ago so it will have a definitive end.

I hope theres like 1-2 chapters of the straw hats all grown up after the find the one piece.

I believe Luffy will find One Piece before the final saga.

He will wage war against the world government as the pirate king, so we will have at least 100 more chapters when that happens.

After obtaining One Piece Luffy will defeat the government in war an after that the manga will end.

I'm guessing a definitive ending, yep.

Maybe Oda will take a nice long well-deserved... WEEEEELLL deserved vacation, and probs just do one or two shortstories/oneshots?

I'm thinking of old generation story.

One piece shall never end.

But seriously, I have always liked anime that go on a little while after the final battle or arc. Just to give the audience an idea of what goes on after the end.