A modded, detailed, lore-friendly take on the castle, turning it into a city controlled by the minutemen. Think Megaton / Diamond city. Inspired by youtuber NoRespawns. This can be performance heavy. I have left inside the walls vanilla to not interfere with quests and for you to decorate yourself.
 

Mods Required:

Transfer Settlements
Homemaker
Thematic and Practical
Workshop Rearranged
Wooden Prefabs Extended
Just Debris
Do it Yourshelf
Creative Clutter
DDP AIO Standalone
G2M
Minutemen Morale
Northland Diggers
Minutemen Propoganda
Wasteland Billboards
Crimsonriders Immersive Market
Box Houses
Vannila Extensions 
Stairs Ladders Ramps
Snappy HouseKit
Business Settlements