Your pretty much spot on there. We use the hand pump 'Pallet Jacks', which I assume you know what are based on your experience, and all our pallets are the large CHEP pallets, the large iGPS, or similarly sized plastic pallets. A good portion of our Pallets are either to heavy to stack, or to fragile, so its generally a single layer, I didn't consider most other situations, where the trailer would be loaded 2 cubes high.
Like I said, it would be much quicker if we had a better floor layout, and maybe quicker with a forklift, but for our operation, we have the manpower on hand for further tasks, so we use what we got, and its unlikely to change, especially in Texas, land of the 'no unions'.