He has a hidden dialogue on Day 1, when you go outside at night and go to the Gate (double click on bottom screen). You should answer "Can't sleep" then "That's it?"
Also, try to avoid Thomas as much as you can, be direct/blunt to Kevin except when you see him in the locker room on Day 4 (Don't say Hi) and the Showers on Day 12 (I don't know)
On Day 13, just help him out without saying anything. Should get you to the camping scene
Kevin and David routes are the trickiest.