What is the plan the duke figures out so they can run in the daytime without putting Jim in danger? (CH 20-23)

The Duke breaks into a printer's shop and takes orders from some farmers. He collects cash and promises to print advertisements in the paper. In his final project, he makes a handbill showing a runaway slave and describing Jim. He tells the others that this handbill will make it seem as if they are taking Jim back to collect the reward.