Yes, well, it's a brick for sure.
I won't be doing any mods to the body itself which couldn't be removed without a trace. Which is another way of saying no mods to the body. I could do something like air dams in front of the rear tires, or a removable cover for the rear wheel wells. The roof is not really clean, the air conditioner is the biggie up there. I'll find a side profile photo on the net and post it.
Our previous small MH had a much more aero overhead cap and transition from the cab to the body. Same chassis and motor, 1 fewer speed on the trans, and it got at least 1 MPG better. I'm not obsessed over the mileage, but I do like to tinker and look for ways to beat the system. This one only has 5K miles on it, and so far it averages right at 10 MPG at 65 MPH. It's better at 55 MPH, of course. As gas motorhomes go, this one is at the high end of the MPG scale. Most, almost all, of them get in the single digits, even at 55-60.