[lunarhighway]

the most practical approach, and keeping everything that has been said before in mind would be to arrange all the cargo in a semi aerodynamic shape, and than enclose everything with a fabric cover... perhaps with a rig like solid airdeflector at the front... if you could hinge this at the front you could even adjust the angle for
the load. perhaps a foldable convertable like cover would be handy...but it would require some skill to put together... a little attention could pay off though over a long trip.