Not much into Cargo Trailers, but always like to think outside of the box ......sorry for the pun!
So my first thought was to have a side access door right at the front one side only so as not to interfere with your fold up cots (wonderful idea by the way)| and have a full galley in the rear that would swing open on a heavy hinge to allow you to load and unload quads.
This galley would be hinged on the opposite side to your rear cargo door.
Once the Quads are out you just close the galley back into position and close the cargo door for travel or security while you are away from the base camp.
With the cargo door open it provides a wind break at a 90 or a long kitchen are when at 180. Also provides a place to attach your kitchen shelter if it is raining.
This could work for you???
Good Roads
Brian & Sandi