With the target of Honeyngton and a description of the old merchant, the heroes can follow the route from the coast ( Havena if they started in Grangor or Perricum if they arrived by ship from Festum, Khunchom or Al'Anfa)
Almost every day will they find someone in the best Inn/Hotel along the way remember the old merchant staying with a young priestess a couple of months ago, though more than once the rumours claim her to be perceived as more of a girlfriend to him.
You can easily insert other adventures along the way.
Finally in Honeyngton they almost loose the track until they hear from a guard on the eastern gate that he saw them leave on a carriage belonging to a farm a few miles to the east of Honeyngton.
(Treat this as an cumulative check: Streetwise (Asking Around), 4 hours. For each check roll a D20 and on a 20 the cultists find out about someone asking around.)
Observing the farm they could spot a carriage with supplies driving further east and then leaving the road on a small trail into the woods, leading into hilly terrain and eventually to an old mine. There are some bandits guarding a few captives and they can find their merchant in a rather poor state but still alive:
Also there is a handful of other old, formally rich, people they can also free:
You can use the other 3 merchant names for them.
They can fight the bandits and the farmer or wait for his departure to free the greatful captives from the bandits.