Toyota Uhaul truck :
What you could do to it :
- remove the mudflaps
- put an airdam under its nose
- fill in the gaps between the cab and the box in a way that leads the air towards the rounded corners (U-Haul did you a favor by already rounding the corners of their box).
- put a wheel cap on the rear wheelshubs, or cover the entire wheel arc
- at the rear : extend the sides & top and taper them inward - it'll make an instant porch / shelter at the rear of the camper conversion.
- wind deflectors in front of the rear tyres
- sideskirts along the lower sides
- clean up the underside with a belly pan.