When you've created some, feel free to share and I can add them to the TravellerMap site. I believe I have all routes from published sources, but they don't cover all of the Imperium, let alone non-Imperial space.
When I made up routes for
Verge my rough algorithm was to take all the Class A starports, whittle the list down so they were roughly 4 parsecs apart, add some Class B starports into the mix as necessary so that most worlds were only 2 parsecs away from an X-Boat stop, then connect them so that each stop served 2 or 3 lines unless near the border.
Completely arbitrary, but then the consensus is that the published/official X-Boat routes don't really make much sense either. And communication routes outside the Imperium would differ wildly. IMHO, they're mostly on the map to look pretty and inspire the occasional adventure.