How route wiring to XM/nav antennas on dash?

sjs50613

I am just finishing a head unit install in our 2010 Touring Roadster (had factory Bose without nav), triggered by a desire to add a reverse backup camera. The new HU (Pioneer AVIC-5100NEX) has a nav antenna, and I also added the XM adapter.

I want the antennas as hidden as possible, so initially tried this with both antennas simply on top of the HU in the dash. Nav works acceptably well there, but XM dropouts are frequent. So I will move the XM antenna probably to the top center of the dash, in front of the gauges, in-between the defroster vents. Maybe the nav antenna also while I am doing this.

Many installs appear to use this location. How does one get the antenna wire routed from the HU up to this location? Along the top of the dash somehow, maybe wedged down between the dash and the windshield? I'm clueless...

I'm looking for some suggestions for this, hopefully not involving major dash disassembly. Or alternate easier, unobtrusive locations to try first.

Thanks...
Steve