I've been interested and a little surprised to read other players' comments about the difficulty level of this game. Thomas' storyline is definitely the default, with a lot of great content, but I was able to uncover some very cool side content even during my first run-through of the game. Kevin was one of the more coincidental storylines (at least the way that I stumbled upon it). It took me a couple of goes to figure out that there was an interaction with Kevin during Day 6 about fixing a car, which I think is what led to me being paired with him for camping on Day 18 (I know from going through the game multiple times that you can also be paired with Thomas for this camping trip, so if you're going for Kevin or another character, I guess you need to avoid that). I kind of riffed off what the characters' personalities seemed like, and because Kevin seems like kind of an aggressive guy, almost that jock / bully stereotype, I made choices that seemed like he would appreciate them and that worked.
Honestly, I spend way too much time on gaming, but so far this game has been thoroughly enjoyable. The art is fucking gorgeous and would carry it no matter what, and the development of the world and characters' storylines is very cool to have seen the evolution of. I'm working on triggering Norman, and most of all Sergeant David, and I think I'm on the right track. I don't feel like I want a walkthrough, but we'll see.