You guys are making this too hard. I have ran several wires from the cabin to the underhood fuse box and it's easy.

Raise hood
Remove cover from fuse box.
Remove inner cover using tabs at the arrows:



Pry up the fuse tray by inserting a flat blade at the yellow arrows:



To the right, under the high current studs, is a channel to the underdash. Insert a NON CONDUCTIVE stick/fishtape/pole/etc., into the channel, it will pop out under the dash (04-06 models, you must pop off the under dash plastic shield above the pedals). Tape your wire(s) onto the stick and pull them back thru. DONE.