*Update* Two weeks until our next outing so I've attacked the entry floor and found what was at one time two 2x4's that are holding up the step. They were so wet I could squeeze out water. I've not found any other water leaks, so I'm guessing/hoping that the 2inch slit in the underbelly next to the screw from the step was the culprit and damage has slowly spread over time. The discoloring of the linoleum has stayed around the entry way and slowly spread towards the bathroom while we've owned the trailer.
I've removed all the laminate flooring in the trailer and plywood near the entrance. It appears the flooring consists of the rubber underbelly, thin plywood, Styrofoam and then more plywood. The damage appears to have stayed at the entry way, however you can where the mold/damage has steadily spread throughout.
Plan now is to repair the rip w/ some flexbend tape, use a couple of pressure tread 2x4s for the step, sand and paint the other areas that have had some mold issues. Good plan, I'm not really sure?