Discover another place, this Cave was there forever but 150 years ago there was mr Crood who build memory portal, but most of the lab is gone to dirt. One of the portals is broken so it get you in present time on top of the one of tallest buildings in Commonwealth. You can settle there until enemies discover it.
You didn't see the cave in game until now because there was machine that makes it invisible, but it's broken now.

I don't know what to rambling anymore. :D


UPDATE

In v3 is fixed map marker and fast travel, added floor on top of the building so now is completely buildable.

Give some suggestions, what you like/dislike, what you want to be added...etc. Also tell me if you run on any bugs.

Hope you like it, Cheers!