For extended cloaking operations, assassinate the Tachyon Guardians two-three systems out. Once you get to un-alerted systems, the group of ships guarding each warp point, and by extension Tachyon Guardian, gets pretty light. Use a Cloaker to get your assassins into place. It is actually pretty efficient and quick, depending on what the AI has unlocked. If they have a tachyon ship, it doesn't work. Astro Trains also make it tougher just because sometimes they suddenly pop through a warp point and uncloak your force.