We want an interior tub.
Like design A. But a bigger effect.
Similar to design B.
My idea for molded plastic would be like design C. Tub plate, and 2 side plates.
Image of interior. Image D
This is the seat for single cab.
Back seat should look like this example attached. (image)
I am okay designing a new dash and steering wheel as well that fits this body, or bodies.
You will need the drawing for the single cab and double cab. May even need the CAD for the chassis with electronics and battery installed. So you know how to make the interior fit with the parts.
Front and rear seat will be bench seats.
(More details will provide when you accept the task. )