This started as an effort for a teardrop with a king--sized bed so that three of us could share it without having to climb over each other. The door was moved to the foot of the bed and a small passage between the bed and kitchen box added. I really liked the idea that you could access the kitchen from either inside or outside. I never got around to building it and no longer need something that big.
I recently started building a small camper to pull with my Prius and after living in my van on several travelnursing assignments realized I really missed being able to stand up. I dusted off the old king-sized camper design and resized it for a full-sized mattress and a small boat trailer I had, keeping the rear door and internally-accessible kitchen layout.
The plan is to build a minimal wood frame of 1x1 screwed and glued, covered with thin plywood, 1" foam, and PMF. The bed is a trifold mattress with a frame that slides together to turn into a couch giving you more floor space or for sitting and watching TV etc