I never liked the transporter tech link--but since it was introduced by JJ with transwarp beaming--a handy thing--here is one way it might work:
You don't beam the ships warp ahead of itself--we will call that a reporter getting ahead of himself as with the Curiosity findings. Instead, like subspace radio that is faster than the ship, the tech acts as a cutwater to allow the ship behind to have an easier time establishing the warp bubble--even as some SLBMs use a spike ahead of the nosecone as here: http://www.fas.org/nuke/guide/usa/slbm/c-4.htm
Slipstream drive just does this only more so. Even as the smoke ring self sustaining Romulan plasma torpedo may latch on to a retreating ships bubble and be drawn towards it--perhaps a ship with a massive star directly ahead might allow a slipstream to feel such a distortion in space (gravitational foci instead of solar foci) and allow faster than normal transit but in straight lines only. Work this a bit more, and you get Star Wars hyperspace lanes?