accessing wet insulation at front of 5th wheeler

We had the same problem. The overflow hose did not drain down through the basement. My husband crawled under the 5th wheel, removed all of the old insulation, drilled a hole in the basement, put in a new hose that drained through that hole, and then replaced the insulation. Sounds like a big job, but it wasn't too bad. Fortunately, the leak was not from the inside plumbing.