I have a bunch of wires I have to route from the engine bay to the trunk ...these are the battery cable (2/0 which is quite thick) fuel pump relay feed, charge wire from alt and one more wire.

I was thinking of running them next to the fuel supply line and zip tying them.....

where do you guys with trunk mounted batts run your cables?

mine are laying on the floor.mounted with zip ties and adel clamps.

I am hesitant about running the power wire with the fuel lines. Not saying it's a problem, but what if something gets kicked up there and damages the lines? It's a possible fire hazard.

I would run mine, if I were to do it, on the inside of the car and through the firewall. The cable would also be dead except at start-up, like this:

http://www.madelectrical.com/catalog/tm-1.shtml