Floating Point Precision in "Infinite" Scene

First off, I already know about the Futurama method (moving the galaxy around you) and it won't work for my purposes.

How would you handle making a ridiculously massive game world, like a galaxy? I've heard mention of using relative coordinate systems but after a great deal of searching could find no useful information on the topic.

The programmer in me feels like the ideal solution would just be having a layered coordinate system. For example a galaxy is broken down into regions which are broken down into sectors which are broken down into solar systems, with each of those layers being an individual coordinate system. I found this solution mentioned a couple times but with no actual information.

Would this be a good solution, and how would you go about implementing such a thing in Unity? Is there a better/easier/alternative solution? Your insight is greatly appreciated.