Dashboard disassembly/wire routing ideas?

I have a 1999 Passat GLX and I've replaced the factory HU with a Blaupunkt Alaska. I'm adding a steering wheel remote control for the radio; the Blaupunkt RC-09 "Thummer". This works by strapping a small infrared transmitter to the steering wheel, placing an IR receiver in a direct line with the transmitter (around the dashboard) and routing a wire from the IR receiver through the dashboard to the radio. Got it?
Now my question. What's the best way to route the wire through the dash? I would like to minimize any hole-drilling etc but I assume I'll have to drill at least one to pull the wire into the dash. From there, I'm at a loss. Any tips?