There is, it should be the default. Unfortunately I can only have 1 2D skybox at a time due to source being really old

Hmm, whenever I try the default is above a lake.

Is it possible to use Atmos?

I think it'd be reall cool if you updated the hyperdrive sequence with the one from the Star Wars: Venator map.

Cool map. I don't understand the admin room though, it would be great to have it explained.
Also something like a room where you can teleport to when leaving the ship. It can be anything, like just a huge room. With the admin room you can give it a theme, like citadel textures. Then admins can fill the room with props etc. Give players a feel they can leave the ship and do something meaningful. Maybe it can be multiple smaller rooms and then through the admin room you can alternate. Or something like a spawnable enemy ship that you can board.
Anything to slightly spice up the map with some out-of-the-ship action :)