I've added some powered rail to the line leading to our neighbor, also buried the entrance somewhat. The entrance near the neighbor is now invisible from minimap and virtually invisible from the surface.
The transfer rail that actually leads to us is now hidden behind a blob of dirt at the [redacted] dropoff, behind a fake mineshaft and a locked door.
I've made a group called Dumagate which I shall start locking doors to. Like the vault I'll give moderator access to all of us, and normal access to anyone we trust to enter the fort, including dale residents if we all agree.
Edit: Whilst exploring and marking out the locations of all our rails and major tunnels I got somewhat lost to the southeast.
Distractedly removing mossy cobble from a torched cave spider spawner I didn't notice the spiders creeping up on me. needless to say i was done for.
Hastily sprinting down the now easily navigable passageways I covered the 800 meters to my death point just in time. As I collected the 2 stacks of power rails I had foolishly kept with me during the exploration, as well as a single diamond and 2 mine carts found within the mines themself more spiders noisily announced their presence.
My hands flew into action and like lightning there was a 3 block thick wall of cobble between myself and the monsters, but now, trapped in a 3x3x3 cell, with nothing to light it but a single redstone torch, I wait for the foul creatures to find a weak point, incessently shrieking throughout the night.