an alternative is to purchase a terminal block and use it in the interior of the van. Connect all your grounds to it then run a single 6 gauge wire from the block to the chassis. Be sure to use a block rated for the amps you have. Terminal blocks make it easy to add more ground wires later on so you have flexibility for future additions to your setup. I have several terminal blocks in locations where I have clusters of switches and outlets, pumps, etc. then from those they feed with a single heavier wire to a primary bock where the single heavier guage wire goes to the chassis. The advantage is fewer wires strung around and a much tidier installation. I am make no claims to knowing everything but at least I did get some experience with building wire bundles and installing them on the jet aircraft at Boeing. So I know that organization is a key to simplifying the job. Of course a good clean surface on the chassis for the bond is also critical as are perfect crimps on the terminals at the ends of the wires.
