Density is only related to gravity when you're up close.
This I wasn't aware of either. I assume this isn't 100% accurate... it seems more logical that density has negligable infleunce at long distance, rather than none? Or am I wrong and that it's a quirk of "nearness"? If so, where's the line that defines "near" and not?

There is so much to gain by asking these kind of hypothetical questions. Sometimes you don't even know where to start, so you start somewhere you know is silly, but you then take it seriously and see what you learn.
Yeah my language wasn't the best. It's not a waste of time at all. Here I am arguing shit that I have no idea about, who the hell am I to say what is and isn't a waste of time!