New - Own 1982 Casita 13' Revamping

[TMiles]

I am working on 1982 Casita trailer and need to gut the interior - headline had ugly foam flooring glued to the walls. I am looking for assistance with wiring and sub floor installation. My 12 volt system doesn't work, not sure why and need some direction as to what might be the reason. Also, the subfloor is dry rot in select places. Anyone take on a similar project in the past or know anyone who has.

I am a newbie that is in it for the long haul - come what may!