So far so good, the exterior shell seems watertight, Time to make the inside cosy.
On the floor I used lightweight foam flooring squares which are weight-saving and warm. It's sorta like thicker yoga matting and its effect is immediate. Such an easy solution.
The floor and lower walls of the original structure are metal; strong, but very cold. Again, in the interests of saving weight, I decided to use polystyrene sheet for insulation. It's light and warm and if any moisture gets in, it won't be absorbed as it would with fibre insulation.
I cut and glued the 25mm thick poly to the inside of the ceiling and walls, planning to cover that with hessian fabric painted with a 20/80 glue and water mix. This mixture binds the fibres and forms a textured shell over the insulation.
The missus insisted on making a contribution and it was my birthday too so, voila, a cover for the mattress, a hanging clothes hamper, thermal curtain for the door, and a rubbish bag holder. How spoilt am I? That rubbish holder takes a dog-poo bag as a plastic liner, easy peasy.
The water container is currently restrained with rope. Short term fix for now, but at least it's not moving during transit. Bamboo pole at upper left fits in brackets at the leading door edge and back to door frame; holds a camo tarp when its raining, or sun-shade, just so door can remain open.
I've installed several air vents to prevent humidity inside and to provide fresh air.
I plan on travelling light, just bedding, water, a small box of cooking/camping gear in one rear corner and camp loo in the other. It's really just a sleeping pod so Gabby and I can getaway and see some new sights.
Security measures. 1. Gabby's a bull-mastiff cross. 2. I've fitted a solar movement sensor and security light at the rear door so if anyone comes near, the world will light up very bright.
Here's to the maiden voyage.