Yea, Red rocket was a challenge for me. I originally tried a large building not that wide, about the length of the build zone and the defensive fence. My game got to the point saying, I'm not allowed to build anything else there. blows my mind when I see builds 10 times the size of my 2 story building. Now I've built one 1/2 the size, the odd part is the "size bar' didn't move much. Jamaica Plains seems pretty large to me, just some worthless buildings in it. I somewhat got a build for it. Hangman, was getting a mod to delete the hut, clearing it, then building upward, avoid the wires. i watched a few videos to get that idea. "place anywhere' would make it easier, but again, it can cause issues a lot of places moving up in hangman you shouldn't be allowed to build into. plenty to block your settlers.
I do still need to come up with something to build a turrent higher. Even half walls are too tall for it, even the defensive fence. keeps shooting the walls instead of the enemy.