Prerequisites: Max out Yorn's level 1 friendship
Reward: Premium Root Beer
Unlocks: Yorn level 2 friendship, A New Frame
Yorn is one of the easier characters to max out on friendship. He spends the vast majority of his day either in or around the Lazy Bowl Tavern, in the south of Moonbury Town. You'll occasionally catch him wandering around outside, perhaps lounging on a bench for a bit, but for the most part he's busy in the Tavern. Check up on him every morning and you'll have your friendship maxed out in no time.
Once you've reached the peak of Yorn's first level friendship bar you'll see a notice on the Bulletin Boards begging for someone to come help out at the Post Office. Dev asks for anyone willing to come visit between 8:00 and 15:00, Monday to Saturday. Dev will give you Yorn's Package, ask you to deliver it to the Tavern, and run off.
Head to the Lazy Bowl Tavern between 10:00 and 18:00 on any day. Dean and Derrek will pass gossip back and forth about Yorn, and he'll scare them away. He'll then accept the package and the quest will end, raising your relationship with the tavernkeeper to the next level. Continue to befriend Yorn and you'll unlock the next quest in his storyline, A New Frame.