Places someone might find the character? Things they might be doing? (1) Gardens, taking care of the flowers; (2) Athletic Center, doing some sports and keeping fit; (3) Beach for some sand jogging.
Is the character in any IC group, including the school? Details! So far, no; but Ken might just try out for Yuuri's Baseball.
What kind of person does the character get along with? Pretty much everyone, actually. Bonus points if you have a dream you want to see through, if you like soccer or sports, you're a kid he can dote on, or someone who likes kids. He's pretty cool with anyone, except maybe those who have disregard for relationship bonds, those who are too snooty (in the sense that their relationship may be off to a rocky start, but not anything that can't be worked with :D), and those who don't care for human lives.
Is there any type of CR you feel the character is missing (e.g. romantic interests, mentor figures, etc)? He's just getting started, but I hope Ken finds steady friends, maybe kids he can treat as younger siblings and a someone he can derp around with (romantically, that is.)
Other notes? It'll take A LOT for him to talk about his assassin days if your character is the curious type. It's not something he can reveal just like that, specially when he's used to being bound by secrecy. ALSO he loves this place :D