Lol, well there actually is a starting point to it all. Smugglers, bounty hunters, the underworld - talk to people/bribe people who have had dealings with the Black Sun, that's bound to turf up the location of several bases. And talk/take over Xizor's suppliers to, if they ship the supplies to Black Sun personally, they must have a few locations.
Xizor can't possibly hide the location of all of his bases. Central bases in particular will likely also be rather well known, in experiences playing the TOR series major crime bases after often known by the locals. I've inflitrated my fair share. And if we recall TCW, Maul has no trouble finding the Black Sun base on Mustafar, nor did he have trouble finding the Black Sun Fortress on Ralltiir or tracking down the Vigos Morn and Darnada. Remember that Black Sun isn't completely hidden, else they could never do buisness. They have 'shopfronts' if you like and well a fortresses designed to act as symbols of authority to the people they controlled (like Jabba's Palace on Tatooine) and that's where Revan would start.
Also if Revan moved fast enough, (he has forces in the Core Worlds) he could invade Xizor's Palace on Coruscant before the Prince has time to erase data on other bases, which could be a very powerful resource.
So that's the starting point, then the cycle begins.
Why didn't you write that in the first place?! It makes much more sense now, thank you. Alright. I'm done. And am ready for complete and utter Traya annihilation. G0_T0 FOREVER!!!!!!