Bathroom - gut, recondition or both?

[TBird156]

I just bought my first Airstream, a 1969 31' Sovereign whose previous owner had lived in it for 10 years. The rear bath is disgusting. Soft floor, odor, discoloration, tub very worn, yellow scum everywhere. He had a garden hose stuck in the wall for his shower. (I know...I am an optimist. I couldn't help myself.) I am uncertain what to do. Can I replace the floor from below and recondition the plastic / fiberglass. OR Do I pull out the wardrobes and anything in the bath that touches the floor so I can replace the floor, black tank, add a gray tank, and build new shower pan / sink & vanity, etc.? Can I pull the tub, sink, toilet, out and leave the upper molded shell? Anyone else have this challenge? Any advise?