I'm guessing you mean barn doors on the back of the trailer rather than doors on the sides'.
I built my first trailer that way for expediency. Each is 2 foot wide and 4 foot high with a pair of standard butt hinges which are more than sufficient.
The doors were constructed of 1/2 inch plywood and covered on the outside with steel siding. One has a fixed shelf for ny Coleman stove and the other a towel rack and trash bag frame.
My galley is pretty standard with a sink in the center counter and open shelves above and below. I mostly use plastic containers for storage of food and utensils and an ice chest. Water is gravity flow from a jug above the sink and another below to collect gray water. No electricity other than battery powered led lights.
If that is what you are planning I'll post a link to the build thread and photos later since I don't have an album here or a link in my signature block.
M C
edit: Build thread and photos
http://www.tnttt.com/viewtopic.php?f=50&t=50714Galley pics toward middle of first page and more at bottom of second.
I would make the doors open 180 degrees rather than 90 to allow better access to the galley interior but it works okay as is for one cook.