Brad : Heed Steve's advice.
Secure everything, I say that after moving household goods 26 times in the military + now. Cover everything, but if it can flap and/or slap - it will also chaff !!
I'd empty the water tanks as they have no baffles and they are easy to empty. On the diesel, I'd guess that who ever regulates interstate shipments, have regulations that dictate what needs to be done.
Just remember that the more padding that is used the better your shipment will arrive in the same shape that it departed.
Watch them pack!! So they don't do stupid things like - ie. a friend had his washer crated for shipment, but the guys that built the crate used nails that were longer than the thickness of the wood!!!!!
Good Luck with your move!!