I have just started doing a project on my Pacesetter caravan it had a kitchen sink under window and cupboards that full length 7ft across the front, I've ripped out the kitchen and left the stove, to the right cleared enough space to put another bed across front (day seat) we discarded the sink as we use a fold up sink more the tap copper pipe still poking up from floor how do you seal it permanently we only use Jerry can water, so this is not required. So all will be pulled out from floor and floor holes sealed, then the rotten piece near window 6" long is it easier just replace bottom timber support or cut out rotten section, and replace,
There is a material like sheeting covering inside wall (I was thinking reinsulate with poly styrene) then veneering it over
Then building a frame for bed boxing it in with hinges (store porta potty & microwave etc) then just adding mattress and back cushion. Job done, is it this easy?