What year and body style are you working on?
I run mine under the door sill plates under the carpet or floor mats on the passenger side of the car up to and then under the kick panels in front of the doors and then up behind the dash and then into the engine compartment so all of the cable is out of sight except in the trunk and engine compartment
I mount my batteries as far back as possible on the passenger side as close to the outside sheet metal that I can get ii safely mounted