If you can hand-carry the SRC or DAT file to the robot, you can do without the DirLoader. That's only necessary if you want to automatically load new modules into the robot.
I've attached a zip file containing some very bare-bones Python converters I wrote that will convert basic G-Code into KRL (either an SRC or a DAT, depending on which converter you decide to use). Might be useful.
I was doing somthing "kind-of similar" using jopenshowvar.. Long time ago i converted the java code to visual basic to make it easier ( mainly for the GUI )