The automatic's costing you a bit of mileage, but clutch-life dropped when they quit making them out of asbestos around the time mine came off the line. I suspect that's the reason almost all RVs now have automatic transmissions.<br /><br />Water weighs 8.5 pounds to the gallon. If you're parking somewhere with water, keeping that tank down to a minimum might save you a bit. You need to keep the blackwater tank primed with some water, but keeping that down to an inch-or-two always might improve things. Grey water tank can be kept entirely empty.<br /><br />But I suspect the wind resistance is something a person needs to study and try to improve in as many small ways as possible. The difference between having the AC on top and after removal was surprising to me, and I think a bit of that was because of that huge cowling up there.<br /><br />Incidently, I edited in a couple of things on the post above while you were writing yours, which you might have missed.<br /><br />If you are somewhere the Ralph Nader factor can be removed, partially or in total, gas mileage will improve. But you might have to reinstall it once a year unless you have a captive mechanic to sticker it.