Welcome!
I think the box has potential, especially the already Kamm'ed rear. Extend that with a hitch-mounted boattail for extra cargo (when not hauling your boat), cover the rear wheels and the gap between the cab and box, and it could fit the template quite well.
When towing the boat, I wonder if you could have some fairings on the rear, extending the wake so the trailer is in it. Or mod the trailer to be a boattail extention.
Sorry, got carried away
I wonder how efficient the drivetrain would be for long trips... Are those single or dual wheels in the rear?
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e·co·mod·ding: the art of turning vehicles into what they should be
What matters is
where you're going, not
how fast.
"... we humans tend to screw up everything that's good enough as it is...or everything that we're attracted to, we love to go and defile it." - Chris Cornell
[Old] Piwoslaw's Peugeot 307sw modding thread