If it is indeed only temporary, you can probably hide it for the most part without taking off a lot of panels (thread it under the rug at the side of the floor, for example.
Also, if it is temporary, you might be able to simply run it underneath the car. There ought to be lots of ways to easily work the wire into the trunk space. I wouldn't recommend this as a permanent wiring approach, but it should work for you. They make wire with some pretty impressive insulation that ought to hold up under the car.
My 2000 is pre-wired for a changer / amp >I just wanted to if anyone has got an amp install in the boot, and how they