I think it's worth mentioning:
You can scale it down and you can "restrict" access, aka just not make the room. If you make a low detail exterior with a medium-detail interior, it could work. When it comes to that slant you mention, ideally you'd just use corner bricks and then make some small changes. Nothing is perfect, and people would understand if you decide to not build the ship at a 43 degree angle.
It's not impossible. I have a 5 story space station, high detail all over, exterior and interior, haven't even made the regular room shells but I have a lot of the props, the brickcount is roughly 60k.
Then again, I'm not a hardcore star trek fan, I just like the original show. I could be speaking way out of my league in terms of ship size.