Sandwich wall: building it "in place" or separatel

[zapj]

I built my frame on the workshop floor then carried it to the assembly shed. You can see that the wall framing was bolted to the floor and frame then the skin was applied.

[Senior Ninja]

We built the walls on a sawhorse bench. We included all the wiring and insulation.
We left a keyway in the bottom of both walls and glued and screwed a key to the trailer floor. We stood up the walls and glued and stapled the walls to the key.
Building on the flat allowed us to use a minimum of fasteners, because we made it a woody.
A third method is illustrated by a man and his son who built their wall on the wall of a small building. A Los Angelos builder tried to hire them to build trailers using the "wall" method.
Steve