I'm inclined to go:
Train Kept A Rollin' (AP 2, HIT 6, REPUTATION 8, OPERATIONS 9)
Grand Theft Person (AP 2, HIT 9, OPERATIONS 7)
Long Shadows of the Night (AP 2, HIT 5, ESPIONAGE 9, OPERATIONS 4)
Smoke on the Water (AP 1, ESPIONAGE 4, OPERATIONS 4)
Pest Control (AP 1, HIT 3, REPUTATION 2)
It's very likely that new time-limited actions will become available on the next two turn. I'd rather finish our obligations ASAP; and leave the Fellowship and the Air in the Valley for another turn.
If we had another time-limited 1-AP mission I'd be inclined to put that in place of Pest Control, but we don't, and at any rate, it might not just be helpful to hunt down Behemoths to possibly help with the Train Kept A Rollin' mission, we also really need money.
...Also also, part of me wonders how many Behemoths Mona can take down without having to worry about collateral damage.