As my primary battery (soon to be 2) is up under the hood on the passenger side tucked right in the corner against the firewall and fender well, I simply followed a set of tube wrapped wires down the fender well to the frame and under the truck. There are grommets (not used) in the floor near the sill of the passenger side front door opening so I simply used one of those and came up thru the floor and then under the carpet. It was nice! With the carpet pad and carpet down and all the trim in place, there is no way you can even tell that there are two power wires coming up through the floor.
I wrapped the power lines with that corrugated black tubing to protect it from any road debris and caulked the hell outta the grommet area, both under the truck and inside at the floor. Worked out very nice. //content.invisioncic.com/y282845/emoticons/cool.gif.3bcaf8f141236c00f8044d07150e34f7.gif