easiest route for cable from trunk through backseat

I recently got a 2001 Prius, and in my old car I occasionally ran an amateur radio. I kept a mag mount antenna in the trunk, and ran the cable between the back seats into the passenger area of the car. The Prius seats don't fold down; what's the easier way to get a cable running from the trunk into the passenger are0a?

A couple spots of rear panel where the rear speakers are mounted is visible from the trunk, I could just poke a hole through it, but I imagine there is an existing route I can take without modifying the car.