Oh - also - what's that on top of your trailer, Junkie? A/C unit? Does it run while you're on the road? Do you use it?
If you don't
need it, take it off. You'll reduce both frontal area (A) and drag coefficient (Cd).
If you don't need it to run while you're driving, you could fab a removable aerodynamic cover for it: round the leading edges, then on the rear taper the shape to blend it back into the trailer roof. That way you at least reduce Cd if not A.
EDIT: PS This is fun - I love managing other people's projects. Easier than actually completing my own!!
