there's a rubber hose that goes from the engine bay to just under the drivers side console for this very purpose. inside, you need to remove the panel above the pedals, and the hose comes out tucked in with all the wires on the left side. you'll have to cut off one or more of the 'nipples' on the end of the hose to stick a wire through.
in the engine bay, it's on the right hand side, protruding from the firewall. you'll probably need something like a coathanger or very stiff wire to feed your wires through. it's probably easiest to start fishing it through from the engine side.