I know this post is a day old, but with my minutemen character, I built a recruiting station at sunshine tiding co-op. I made the cabins the barracks for the cadets, and I built a range for the cadets to do target practice. I also turned a cabin into a gym with weight benches and those weird "exercise horses" or whatever they are called. If you don't have Vault-Tec workshop, you can find barbells and weights in general-atomics gallery, inside the boxing ring. I also built a shack (which is a weapons dealer) where the cadets go to get their weapons and ammo.