From a base on the surface of Titan or in orbit around Titan it will be possible to fly to most of Saturn's moons in a reasonable amount of time.  It will take the same amount of time to fly back by Hohman orbit to Titan. Launch windows given by the synodic periods are not too far apart.  As for Hyperion, you can get there in 9.9 days but you need to wait about two months between launch windows.  Phoebe is 113 days away by Hohman but there are faster orbits.  Propellant will be obtained simply by excavating water and ammonia ices from the surfaces of Saturn's moons, melting them down and filling up the ET spaceship tanks.  This will be quick, cheap and easy.  Using liquid ammonia or water instead of LH2 will make construction of refueling stations on Saturn's moons a snap.  Propellant will be shuttled up to orbiting ET ships with NTR vehicles similar to Anthony Zuppero's "Zuppmobile" or the Mark Maxwell Ice tanker.

BELOW) The Mark Maxwell ice tanker.  The Kevlar bladder is filled with water or liquid ammonia and a solid core fission motor provides thrust. Robotic vehicles such as these could efficiently ferry loads of propellant up from mining bases on moons of outer planets to orbiting ET ships.

BELOW) ET ship drawing by Dennis Martin based on design by Dave Dietzler