For the mountain, maybe this thread will get you started. It may make your polycount crazy high, though. Another way would be to take a plane and just start pulling and pushing. Another way would be to just start with a cube primitive and start splitting polygons, extruding this way and that. That would give you the rough, look of the one sketch with the station tucked in the mountain cliff.
"Terminat Bora Diem, Terminal Auctor opus."