Next came some carpentry...
This is not where my skill set lies and nor did I have the tools for it. I bought a cheap miter box and saw and a Kregs pocket hole jig and clamp.
From there we started work on the bed. My phone died so I lost the build time lapse but here is a quick clip of the working product. I took my wife and I the better part of one full weekend day and a couple of week nights to finish.
We used 2x3 for the frame. The bed storage is divided in two spaces. The front section will be for storage.
The other(rearmost) will house a slideout kitchen(camp stove and cooking work surface) and just below the hinged lid a shallow tool box area for regular hand tools. We used tongue and groove for the bed sliding mechanism and lid..the result is more stable sliding/hinging performance then the standard slideout bed designs that most use. Its 28" wide and expands to 50". I'm a mechanical engineer, and I really wanted to make this build lighter, faster, stronger, but alas our scales failed and we neglected to get a weight. I will say it seems to be less than the 80lb piece it replaces. I could hold the 2x3 frame(no lid or tongue and groove) up in one fully extended arm. I have since priced balsa, carbon fiber tubing, etc and all seem unrealistic for a low budget build.
I am honestly quite happy with the way it turned out. We still have the slideout to build and we'll add a fascia and some skins on the box to enclose it.