Ask him where to find his friend

"Glad to see you are reasonable about this," says the gremlin. "If you take the path through the woods and turn left at the river, you'll come to a cave. That is my friend's residence. Tell him Bartholomew sent you and he'll tell you what he needs from there."

You can still change your mind and continue to the river

or

you can pursue this new adventure and find Batholomew's friend.