Hi. It is delightful to discover you are in Canada and a Tradewinds owner with mucho experience.
My Tradewinds (395LE) was assembled in 2003.
You provided helpful pictures and narratives about replacing carpet with (vinyl) flooring. I chose cork.
The soft spots in the subfloor (between the captains chairs, and in the center near computer station) are not water related, I think. No visible sign of standing water, nor delamination. These two areas seem to be over the diesel fuel tank. My water storage is midship. I tried epoxy to provide rigidity - no joy. Your suggestions are welcome.
As would be a 'novice navigation of IRV2 forums and posting'.
Gary near Longview AB on the eastern slopes Rocky Mtns.