Not that you asked...
Have you identified and corrected what caused the floor to go soft? "In front of the sink" may indicate a leak in the water/piping system.
I bought a 2001 trailer with obvious water damage in the front right corner and walls. Being new to trailers, I didn't [S]realize[/S] apply the fact that the water always finds its way to the lowest areas (floor). There was much more repair than I anticipated, but the trailer (after DIY repairs... er, corrections) is working for us.
I found that the roof had leak problems, the wheel well arch assemblies had problems, and likely the outside covers on water inlets and other covered openings had issues.
Anyway, my point is that you should be certain to check and correct leaks before repairs or the problems will return. Leaking water will often insidiously creep around unnoticed.
Good luck. vic