If the New Horizons team doesn't find a KBO target for the probe, can they turn it into an orbiter for the Pluto system? I know entering orbit right now would be impossible, but would it be possible to achieve this by making a first fly by, turning back and getting some help from Saturn or Jupiter in the future years?
See this video of New Horizon's trajectory. After it flies by Pluto, it's not coming back. It's leaving the solar system on a hyperbolic trajectory.
Edit: If the hyperbolic periapsis was moved to within 10 km of Pluto's surface, the turning angle would be increased to about .4 degrees. Not much of a path change, not sufficient to send it back towards one of the gas giants.
It is my understanding that New Horizons does not have sufficient reactive control energy to establish an orbit about Pluto.