Hi Ploughman,
To route audio input to audio output, you can use the monitoring system.
I think this is explained in the manual.
To set up the monitoring : set the output for Monitoring in the audio output panel, in the Input Window, move up the monitor fader (most left fader in the Input Window), then, you will hear the audio input in your output (but with some latency, regarding your audio settings).
To use a VST instrument in an input : create a stereo input in the input settings panel. add one insert slot in this input (in insert preferences panel), then, in Logelloop, load a VST in the input. In the VST insert, load your instrument. Then, you can route a midi device to this insert (midi preference panel).
Hope, that will help,
Thanks,
Philippe