I think Sarah TN gets the final rose.
I don't know why some people see no chemistry -- if there was no chemistry Travis would interact with Sarah TN like he does with Tara. There is a sense of tension between Sarah TN and Travis that could translate into attraction, only both people are moving slow (or as slow as you can on this show) and the editing is hiding things as well.
I personally see no real chemistry between Travis and Susan (zippo there) or between Travis and Sarah B. (just frat boy/girl kissing and cuddling there, not adult passion, IMHO). I don't dislike Susan or Sarah B., I just don't see it. (PDA's do not always equal real passion).
Nothing with Tara, obviously. Not enough time spent on Jehan to determine anything yet.
I think there is a real attraction with Moana as well. So Moana and Sarah TN are my pick for the final 2.
I have no proof, but I have been right on this in the past so I am going with my instinct/intuition!