Instead just loaded up Fallout 3 and New Vegas.
I kind of understand the layout of Vaults 112 (real small and simple) and 22. {Bit more complex}
Looking at the current Fallout 4 Vaults, I'd have to go with 81 for the open cafe area, and remote reactor area.
I've only made hallways, stairs, doors and shit. Have like two domestic setups on 2nd floor, for settlers.
On the end of a tunnel leading to one of the exits, is this dude: