Ultra-cold neutrons can move relatively far. With a lifetime of 886 seconds, they could potentially move several miles before decay.
Apparently, even at near absolute zero - they still achieve about the same velocity as a human running fairly fast. Wiki sez: The kinetic energy of 300 neV corresponds to a maximum velocity of 7.6 m/s or a minimum wavelength of 52 nm... and can be described as a very thin ideal gas with a temperature of 3.5 mK. http://en.wikipedia.org/wiki/Ultracold_neutrons
