I'm not totally convinced the teardrop is all that aerodynamic. You'll notice that the back end of most SUV's or even fuel efficient cars aren't shaped that way. I'd guess that the shape of the rear end makes very little difference compared to something like reducing the roof height or moving the trailer closer to the tow vehicle, or even adding a splitter plane on the back (spoiler) where the air delaminates. The "Kammback" designs have proven to be very low drag and still have more useable space. Like the back of a Prius. So I'd have a slightly curved roofline, but a square back. More like this:
And that way the doors open out to the sides - or one side - and you can have a full set of cabinets and fold down table mounted to the door and have a much larger effective kitchen area.
I didn't design mine with any meaningful evaluation of aerodynamics. I just went by what I though looked good. It's okay - but not ideal by any means.
the goal is to disrupt the airflow as little as possible. the prius is a perfect example... they found the shape that was most efficient without needing a long tail. Look at the shape of a wing on a plane....tear drop
here... "While the realities of fluid dynamics dictate that a teardrop shape is the ideal aerodynamic form, Kamm found that by cutting off / flattening the streamlined end of the tear at an intermediate point, and bringing that edge down towards the ground, he could gain most of the benefit of the teardrop shape without incurring such a large material, structural, and size problem. The airflow, once given the suggestion of the beginning of a turbulence-eliminating streamlined teardrop tail, tended to flow in an approximation of that manner regardless of the fact that the entire tail was not there. This is called the Kamm effect. " (Kammback)
