So, who's the father?

It wasn't a cliffhanger--Rory's life is now going to proceed as Lorelei's did. She's pregnant with the rich boy's child, tries occasionally to make it work with him while raising an entitled spoiled child, and will eventually wind up with her true love--the "rough" sweet guy.

Either Logan is the father and it proceeds exactly as said above, and Rory has a daughter that becomes Lorelai n°4, will be dealt a brilliant future on a platter that she will eventually throw away for a much more wholesome life in Stars Hollow where she will make a living running a book/coffee shop,have her heart broken by a rich bad boy and by 2046 marry some Dane cousin that we don't know about.
Or the father is her Chewbacca one-night-stand, and that's going to make a much less savory story to later tell her kid (which is going to be a boy, because the Gilmore Girls line has to stop), and it would serve her right.

It's pretty safe to say that it's Logan.