Welllll, there are already a ton of teens/young adults over in Alexandria, so I'd understand if you wanted to put him there. However, I think it'd be pretty badass to have him in The Sanctuary. Though I'm not sure how well he'd take the things Negan has done as punishment to his own people.
Though there are plenty of saviors who don't agree with his methods but do what's needed in order to survive. Maybe they could be part of the work group, which would give them more freedom to come and go and not be apart of what Negan does, as long as they brought him back stuff to sale in the points system. Or if you wanted to make Bruce darker than he is, Negan would probably take a shine to him pretty early on. Much like he does with Carl. (I play Carl so it'd be fun to play that dynamic with someone other than myself lol)
EDIT: Also, hi! I'm Chels and one of the mods here. I don't know why I'm always forgetting to introduce myself. I think I just get too excited about plots and jump right in!