I've decided to (eventually) make a mod to move the planets to their positions in Legends for GC only (I'm not touching the campaigns with a barge pole). I've cracked open the trade routes and planets xmls, and it looks deceptively straightforward... except one thing:

I have no idea where the hyperlanes that aren't trades routes are. The normal connections for fleets to travel on. Does the game process this on it's own (doubtful), or is there something I need to dig up yet?