So just got the scene and here's how:
First, you have to encourage Logan to go to the bandit camp so you enable his bottom route. Also level up strength or equip a bonus damage weapon to help Logan with his work to gain a little bit of relationship points with him until you no longer can. You must progress with Bernard's missions and relations to have him plan out the fair. Once you have the fair event available, go the fair and choose the option "stroll around". You may have to talk to Rose a few times but just ignore her and continue to "stroll around" until you see Logan and Korg interaction. Don't forget to invite Korg to the fair, Logan does not need an invite; he cums ( :D ) there automatically for you