You could bang together a quick-and-dirty cap that rose gently to meet the height of the Uhaul's roof, and sides that flared out to meet the width of its walls. Take those as far aft as you dare, bearing in mind that you'll spend the majority of your time on Interstates with gentle turns. The closer you get to making them meet, the less turning tightness you have left, obviously.
If it were me, I wouldn't do more in the time frame you have mentioned. I wouldn't waste a lot of time and effort on a one-and-done like this.
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Lead or follow. Either is fine.
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