I did use rotc on sanctuary but only one time now, just wanted to see how it was from 0 -3 but now I do it myself how I want it , I did like some things, but I thought there was maybe one too many factories being build for the amount of settlers there's and a little too clutter for my liking, some npc's pathing bunches them up with others, ..
But in terms of graphics sanctuary hill was just fine, tho sometimes the fps was hard to maneuver around =(
Not sure about red rocket , I never got around to using rotc with that, I keep that area for personal storage and to get away from the settlers and whiny marcy never being happy with what was done