I think your inverter is going to squak at you as soon as you turn the fan on. The wiring in your rig will not support the current needed to run your inverter and fan. As others have said, wire the inverter within a foot or two of the batteries. I'd use at least 6 Ga wire. You can then figure out how you want to deliver the inverter power into your rig. Either an extension cord, a special outlet that just runs from the inverter, or a transfer switch to power the whole rig (very technical to install this way).