My colonial fort. This is the Mk4, due to the Mk3 breaking up (in transit to Piece by Piece South Hants then being rebuilt while there and then collapsing on the return journey). As a result it is built in modular form with each section of wall ten studs long so it can be dismantled for storage or packed safely for transit. The interior structures consist of a water tower, ablutions, the magazine, officer's quarters and a barracks.
The outpost is on a nearby hill and can be manned to give advanced warning of any attack, it's gateway faces the fort and when not in use the gates are taken by cart to the fort to deny its use to an enemy.
Forts are important. There aren't enough out there. When the actual killing begins, your project will receive the attention it deserves. Until then, continue to build reinforced structures and continue to garrison them with correctly trained and equipped troops. You might consider adding a well or water tower. Good stuff.