"The caravan's mostly hauling mundane supplies.  There's two covered wagons and a carriage for the merchant and his wife that own everything.  We've talked to them to explain the plan, but we've been careful to not let anyone else know about it.  If the culprits have agents in the city, they won't know about it.  If you want to hide in the wagon, we can make sure you're hidden before it sets out - meet at the Broken Wheel inn at about noon.  As for how successful the plan would be... well, that's up to you, but it seems a solid idea to me."