Here's a pic that Smokehouse took at a recent hang...pardon the mess.
I elected to use a steel hammock stand, rather than hanging from the van itself. That allows the hammock to tuck in close to the driver's side side wall, freeing up the remaining space in the van. The van is a standard length, half ton Chev, and the hammock is a GT Double.
Hppyfngy makes a good point: height of hang is critical if you're to preserve adequate sag and concurrently, ground clearance.
I looked at this pretty hard before buying my van...I hope this helps, and will be glad to answer any questions you may have.