One thing to remember about installing the GPS is not to use any magnetic material around it.

Install the GPS away from any servos. 

It's recommended to install it midway down the tailboom.

The Trex600 stabilizer belt matches the GPS' mounting holes.  Drilled right through the screw holes.  Inserted tie-wraps.  Used rubber washers to act as spacers for the gap underneath the GPS.

Tied down the tie-wraps.

Used fuel tubing again to protect the GPS wire.

UPDATE:

Change to aluminum stabilizer belt and stainless steel screws.

This is much more secure.

Plugged in the GPS into the adapter's port #1.

Tied down the GPS wire with protection.

Hardware installation complete.