Well, here's what I'm noodling around with currently:
Build a galley with cabinet doors that open from both sides - either via slider or hinges. Access is available from inside and outside. Also have bi-fold or pocket doors that partition the area between the upper cabinets and the counter top. This way I can close off the area from the sleeping area or open it up for air/sun during the day.
Which all sounds cool in theory, but I might need deeper shelving and counter space than I'd originally planned. I was hoping to designate about 24" of trailer depth to the galley area, leaving me with 8 or 10 feet of sleeping/storage area, depending on whether or not I get a 6x10 or 6x12.
So then I got stuck, wondering if building a sink in the countertop was a wise idea or not. I was planning on going semi-primitive, with a 5 gallon Sparkletts style jug underneath the counter with a hand pump up to the sink with a second one for grey water return, but now I'm thinking I can put that contraption on a table outside and be done with it.

Then the space where the sink would have been gives me a larger, more protected food prep surface area.
This is why I need help!
However, Prem, you just gave me an idea - back to the sketch pad! I will have to take some pictures of my crude drawings and post them once I mull this over a little more.