Todd, I leave my cells for the truck inside the front windshield. I park it half sun/shade type but if I had the luxury of running a line two it, I would either use a large diameter wire or double staking it with two smaller wires in parallel. When I use to work at the Rocket Ranch (Nasa), a lot of critical wires for sensors are ran double staked. It serves two purposes.
1. Adds redundancy in the event of a damaged/broken wire
2. Reduces the voltage drop of the wire by half and allowing more current to flow reducing energy wasted by the wires acting as a resistor giving it off in heat.

Look as a wire as a resistor, measure the wire at the distance say 100 feet, now put another 100 foot in parallel with that wire and remeasure, it should be half the resistance if the two wires are equal. Doubling your wire may get expensive but it is effective, a bigger wire may be less expensive. You would have to figure out the savings. I'm just saying there are several ways to do it, I would use a larger diameter wire with the shortest distance if possible.