There will be others chime in on this soon but it sounds like a typical newbie approach to AutoCAD, that is you are trying to "draw to a scale" rather than "present what you've drawn to a scale". You can of course do this with AutoCAD but it just complicates your work.
Instead, you will want to draw all things in model space to a 1:1 scale. It doesn't matter if it's 1" or 10,000 light years. AutoCAD is basically an infinite universe and you are not limited by scale.
Once you have drawn your objects at full scale in model space you can use several different methods to present your drawing, either to file (PDF) or to a printer, using an appropriate scale for the media (paper size) you are using. I know this is always a difficult hurdle for new users to grasp, but once you master model space and viewports, you're on way to drawing anything, anywhere, to any scale. Think of model space as an infinitely large canvas. Don't limit yourself to the size of the paper you're working with. That's what AutoCAD is made to take care of for you.